To be fair most, if not all of the technologies in Bitcoin existed prior to Bitcoin, or outside of Bitcoin.

So from a technology standpoint hypothetically Nostr could have existed with Bitcoin.

I think where Bitcoin's role plays into Nostr is the community, and funding.

With XLon Musk banning Bitcoiners, and Cryptocurrency people on twitter maybe people like Fiatjaf, and Jack wouldn't have been inspired as much to create a new alternative.

As we see, there are plenty of non-Bitcoin focused alternatives like Gab, Mastodon, PanQuake, etc. but

So it's hard to say, overall history plays out the way it does, and nobody can change the past except The CIA 🙃.