A lot of new nostriches are curious about how NOSTR works and how it relates to bitcoin, they both use Cryptography, not cryptocurrencies.
It´s something that can only derive public keys from private keys, it doesnt work the other way, that´s the beauty of it. so you cant steal bitcoiners money if that is what you were thinking .
private key----------> public key
public key xxxxxxxxxx private key
It´s a one way secret .
that makes it a discovery of nature , almost godly like to be able to post something public without getting to your identity at the same time, there is only one way.
But that also comes with a lot of responsability, because if private key is compromised, you lost your bitcoin and your nostr identity, and have to start again. The private key is your login and password at the same time, the public key is just your username.
follow @KeithMukai , seedsigner creator, he is working on a way to derive your nsec nostr key from the bitcoin seed, they can be derived from the same path, yes. And your bitcoin will still be safe.
https://dergigi.com/2018/08/17/the-magic-dust-of-cryptography/
if you want to go deeper!