Import from Nginx rewrite rules?

Yes, to an extent:

https://redirection.me/support/import-export-redirects/

Actually, sorry no – Nginx rules can’t be imported.

Nginx Rewrite Rules

Standard Nginx rewrite.rules files can be imported. Note that only redirects that match directly to Redirection redirects will be imported.

What do you mean with: “only redirects that match directly to Redirection redirects will be imported“?

As I said, Nginx rules cannot be imported. The documentation is incorrect and has been updated.

Uh… ok. Thanks.