Here’s the URL you’re looking for - just add your email address:
https://teams.microsoft.com/l/chat/0/0?users=<your email address>
This is a deep link you can also add an initial message and create/name group chats from the link. You can find out more about deep links here: https://learn.microsoft.com/en-us/microsoftteams/platform/concepts/build-and-test/deep-link-teams