Is it possible to get user access token with REST API?

We are trying to implement an utility to access USER’s asset in NUCLEUS. How to get the access token?
Suppose, user is willing to provide the username and password, is there any REST API to do it?

Such as, use REST API to retrieve user’s access token (and refresh token), and use some http POST, GET to access NUCLEUS with the access token in Bearer Header?

…is there any REST API to [get an access token]

No, we don’t support a REST API for Nucleus.

The omnicli sample exercises many of the Omniverse Client entry points. It might already have what you need, or you could add a command. Although, I don’t see entry points for generating and retrieving an access token.

How to get the access token?

The only way I know is through Navigator. See this documentation for more information about API Tokens