A NOSTR pub key is derived from the same seed phrase as your BCH addresses. But just one key, so there's consistency, not a whole sequence like with the addresses.
In the future we'll add ability to switch keys for different profiles.
Discussion
I assume you saw the bug report at the end of that last post. Also, as a reply to myself, I paid only myself, but presumably that's intentional or at least works out for practically free threads (assuming it doesn't get abused)? Notification for "custom tip" by that reply said it was anon, though...