How to prepare for MTD ITSA in Nomi: A guide for accountants

Team Nomi

Aug 05, 2026
9 minutes read

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Making Tax Digital for Income Tax (MTD ITSA) is changing how eligible sole traders and landlords manage and report qualifying income to HMRC. For accountants and tax advisers, preparing your practice and clients in advance is an important part of getting ready for quarterly reporting.

If your practice uses Nomi, there are several steps to complete before you begin configuring MTD ITSA for individual clients. These include setting up the right HMRC access, completing authorisation, generating an access token, checking client eligibility, and confirming that the required client information is correct.

This guide explains how to prepare for MTD ITSA in Nomi and what accountants should have in place before moving on to the setup stage.

What you need before preparing for MTD ITSA

Before configuring MTD ITSA in Nomi, make sure you have:

• An active Nomi account with appropriate permissions.
• An HMRC Agent Services Account (ASA).
• Government Gateway or Government One Login credentials linked to the ASA.
• Authority to act for the client, where applicable.
• The client’s National Insurance Number (NINO).
• Confirmation that the client is registered or eligible to register for MTD ITSA.
• Internet access to connect securely to HMRC services.

Once these prerequisites are in place, you can move on to configuring MTD ITSA in Nomi and preparing eligible clients for quarterly reporting.

Why you need an Agent Services Account

An Agent Services Account (ASA) is HMRC’s dedicated online account for tax agents and accountants. It enables authorised practices to access HMRC’s Making Tax Digital services on behalf of their clients.

An ASA is different from a standard Government Gateway account used for services such as self-assessment or PAYE. It supports digital tax services, including MTD for VAT and MTD for Income Tax.

Nomi uses the ASA to establish a secure connection with HMRC and communicate with its MTD services.

Who needs an ASA?

An ASA is required for:

• • Accountancy practices.
  • Tax advisers.
  • Bookkeepers acting as authorised agents.
  • Organisations submitting MTD ITSA returns on behalf of clients.

Clients managing their own MTD ITSA obligations directly with HMRC do not require an ASA, but they must still register for MTD ITSA where applicable.

Why is the ASA important?

The ASA enables Nomi to:

• • Authenticate with HMRC.
  • Retrieve client MTD information.
  • View quarterly obligations.
  • Submit quarterly updates.
  • Receive HMRC acknowledgements and responses.

When authorising Nomi, use the credentials associated with your practice’s ASA rather than a personal Government Gateway account.

Government Gateway and identity verification

When connecting Nomi to HMRC, you will be redirected to HMRC’s secure authentication page.

Depending on HMRC’s authentication process, you may sign in using:

• • Government Gateway credentials, or
  • Government One Login credentials, where supported by HMRC.

Agents should use credentials associated with their ASA. Individual taxpayers managing their own MTD ITSA obligations should use their personal HMRC credentials.

During the authorisation process, HMRC may also ask you to verify your identity using methods such as

• • Passport details.
  • A UK photocard driver’s license.
  • Other approved identity verification methods.

These checks are performed by HMRC and are not managed by Nomi.

How HMRC authorisation works

Before Nomi can communicate with HMRC, authorisation must be granted. This allows Nomi to retrieve MTD ITSA obligations, check client registration status, submit quarterly updates, and receive submission responses.

The process is

1. In Nomi, navigate to the MTD ITSA settings.
2. Select the option to connect to HMRC.
3. Sign in to HMRC using your ASA-linked credentials.
4. Review the permissions requested by Nomi.
5. Grant authorisation.
6. Return to Nomi, where the connection is completed.

Once authorisation is successful, Nomi stores an access token for secure communication with HMRC.

Best practice: Ensure authorisation is completed by a user with appropriate permissions within the practice.

Understanding HMRC access tokens

An access token is a secure digital credential issued by HMRC after successful authorisation. It allows Nomi to communicate with HMRC’s APIs without requiring you to sign in for every request.

The token is used to:

• • Retrieve client obligations.
  • Check MTD status.
  • Submit quarterly updates.
  • Receive HMRC responses.

The token is generated during the authorisation process and securely stored by Nomi. No manual token creation is required.

Access tokens have a limited validity period defined by HMRC. If a token expires or is revoked, Nomi may no longer be able to communicate with HMRC and you may need to repeat the authorisation process.

Why the National Insurance Number matters

The National Insurance Number (NINO) is a key identifier used by HMRC to identify individuals for Making Tax Digital for Income Tax Self Assessment (MTD ITSA).

It plays an important role in:

• • Verifying the client’s identity.
  • Matching the client with HMRC records.
  • Confirming the client’s MTD ITSA registration status.
  • Retrieving quarterly obligations and submission information.

Before preparing a client for MTD ITSA, always check that:

• • The NINO is entered correctly in the client’s record.
  • The NINO has been typed manually rather than copied and pasted, as hidden spaces or special characters can cause validation issues.
  • There are no typing or formatting errors.
  • The NINO matches HMRC’s records.

A missing or incorrect NINO can prevent successful registration, stop HMRC records from matching correctly, and lead to issues when communicating with HMRC.

Checking client eligibility for MTD ITSA

Before enabling MTD ITSA, confirm that the client is eligible.

Step 1 – Identify qualifying income

Check whether the client receives income from:

• • Sole trade(s).
  • UK property.
  • Overseas property.

Step 2 – Calculate combined gross income

Add together the client’s gross income from all qualifying income sources to calculate their total qualifying income.

For example:

When you select Calculate Qualifying Income, the software checks the client’s qualifying income against HMRC records.

If the verified qualifying income for the 2024-25 tax year is more than £50,000, the client falls within the mandatory scope of MTD ITSA from April 2026.

Once the income has been verified, you can continue with the remaining MTD ITSA preparation steps.

Step 3 – Confirm registration

Check whether the client has already registered with HMRC for MTD ITSA or needs to complete the registration process.

Clients cannot submit quarterly updates until they have successfully registered with HMRC.

Step 4 – Confirm agent authority

If you are acting on the client’s behalf, ensure the client has authorised the practice to interact with HMRC.

Check that the authorisation is active before attempting to retrieve obligations or submit updates.

Step 5 – Verify MTD status in Nomi

After registration and authorisation:

• • Refresh the client’s MTD status in Nomi.
  • Confirm HMRC recognises the client as an MTD ITSA participant.
  • Ensure quarterly obligations are available before preparing submissions.

Preparing clients with multiple businesses

Some clients may have more than one qualifying income source, such as:

• • Multiple sole trades.
  • A sole trade and UK property income.
  • UK property and overseas property income.

Each qualifying business must be correctly identified and linked within Nomi, as separate quarterly obligations may apply.

For example:

Nomi will retrieve and display separate obligations for each qualifying business, allowing them to be managed individually.

MTD ITSA preparation checklist

Before moving on to the setup stage, confirm that:

• • The Agent Services Account is active.
  • Government Gateway or Government One login credentials are available.
  • Nomi has been authorised with HMRC.
  • The access token has been generated.
  • The client’s NINO has been verified.
  • The client’s qualifying income has been assessed.
  • The client should be registered for MTD ITSA if qualify.
  • Agent authority is in place, where applicable.
  • The client’s MTD status is confirmed in Nomi.

Best practices when preparing for MTD ITSA

To prepare your practice and clients:

• • Use ASA-linked credentials, not a personal Government Gateway account, when authorising Nomi.
  • Verify the client’s NINO before connecting with HMRC.
  • Confirm the client is registered for MTD ITSA before retrieving obligations.
  • Keep HMRC authorisation active and renew it promptly if access is lost.
  • Review clients’ qualifying income annually to determine whether they fall within the mandatory scope of MTD ITSA.
  • For clients with multiple qualifying businesses, ensure each business is correctly mapped and monitored separately in Nomi.

What happens next?

Preparing your practice and clients is the first step towards successfully managing MTD ITSA. Once you have the necessary HMRC access, client information and authorisation in place, you can move on to configuring your MTD setup and preparing for quarterly reporting.

Using the right MTD software can help your practice manage the requirements of Making Tax Digital for Income Tax in one place, from connecting with HMRC to managing client obligations and quarterly updates.

Ready to prepare for MTD ITSA?

Get your practice ready for the next stage of Making Tax Digital with Nomi. Set up your HMRC connection, prepare your clients, and manage your MTD ITSA requirements with accounting software built for modern practices.

Ready to get started? Start your free trial today.

Frequently asked questions

1. Can my accountant register me for MTD ITSA?
   Ans. Yes. An authorised accountant can register you on your behalf using their HMRC Agent Services Account. 
2. Can I use my personal Government Gateway account?
   Ans. Individual taxpayers can use their own Government Gateway or Government One Login credentials. Accountants acting for clients should use their Agent Services Account credentials. 
3. Why do I need to verify my identity?
   Ans. HMRC uses identity verification to protect taxpayer information and prevent unauthorised access to tax records. You may need to verify your identity before accessing MTD services. 
4. Why can’t HMRC find my client?
   Ans. Check that the client is registered for MTD ITSA, agent authorisation is complete, the National Insurance Number is correct and the client’s details match HMRC records. 
5. What if HMRC says my client is not registered?
   Ans. Confirm the client’s eligibility and complete the registration process if required. Once HMRC has processed the registration, refresh the client’s status in Nomi. 
6. Can I register for MTD ITSA voluntarily?
   Ans. Yes. Taxpayers below the mandatory income threshold may be able to register voluntarily, provided they meet HMRC’s eligibility requirements. 
7. How long does MTD ITSA registration take?
   Ans. Registration is not always immediate. Allow time for HMRC to process the registration before retrieving MTD obligations or submitting quarterly updates. 
8. Can I deregister from MTD ITSA?
   Ans. You cannot simply opt out once you are within the mandatory regime. You may leave MTD ITSA only if you meet HMRC’s exit conditions, such as falling below the applicable threshold, ceasing qualifying businesses or qualifying for an exemption.