How do we export and import Teams Chat Contacts ?

There's no export or import for Teams Chat contacts, and no supported way to sync them across accounts. The "Import contacts" doc that turns up in search only covers Exchange and Outlook contacts, so it won't help you here.

Chat contacts are a per-account list tied to that mailbox, with no export button and no API path to them.

Your options:

• Rebuild by hand. Tedious, but it's the only supported route.
• Check your Outlook contacts for overlap. Those do export as CSV (File > Open & Export > Import/Export) and import into another account cleanly.
• Vote on the Feedback Portal request, which won't help you today.

No GPO, cmdlet or export tool reaches this list. It sits outside both the Teams admin tools and the Exchange export paths.

This outdated... there is no Settings under Photo.. its next to it.. and no feature to Backup contacts

Exporting Teams chat contacts:

1. Sign in to the Microsoft Teams desktop app.
2. Click on your profile picture in the upper right corner and select "Settings".
3. In the Settings menu, select "Privacy" and then click on "Manage contacts".
4. In the Manage contacts window, click on the three dots (...) and select "Export contacts".
5. Choose a location to save the file and click "Save".

Importing Teams chat contacts:

1. Sign in to the Microsoft Teams desktop app.
2. Click on your profile picture in the upper right corner and select "Settings".
3. In the Settings menu, select "Privacy" and then click on "Manage contacts".
4. In the Manage contacts windowhttps://gbwa.dev click on the three dots (...) and select "Import contacts".
5. Select the file that you exported previously and click "Open".
6. Your contacts will now be imported into Teams.

This process will only sync the contacts within one Microsoft 365 account. If  syncing the contacts across multiple accounts, you need to repeat this process for each account.

mwilcox1SOD 

please check this resource: How to export Migrated Teams Chat from outlook and import to MS Team - Microsoft Q&A