very general question - does anyone know of any projects that use kratos to authenticate NATS users? I believe I could do this using hydra to generate JWTs and authenticate NATS using JWTs but we have a pre-existing architecture which is based on kratos and uses sessionIDs.

You could use this endpoint to convert the kratos sessions into JWTs: https://www.ory.com/docs/identities/session-to-jwt-cors would that work for NATS and your architecture?

Thanks, I am afraid it would not