There's no dependency as such.

But most of the devs who build Nostr clients and early users are from Bitcoin community

Hence, a lot of Bitcoin discussion & there's also zaps on Nostr- you can reward the author of a note by sending them sats (very small unit of Bitcoin equivalent to 100th of a cent) using Lightning.

Zaps require a Lightning wallet but that's optional. You can use Nostr completely zap-free like I do, however, you'll miss out on a few features -that's all