I'm not sure how effective that would be. The costs of maintaining a fork are quite high.
Here is an idea which is lower cost and potentially friendlier to the maintainers:
what if they could create a repo event which highlights that they are not the maintainer (empowered to merge code on the repository / a repository that other people are using as an authoritative codebase)?
If those they see as maintainers are on nostr then they could add them, even if that maintainer hasn't created a repo event yet.
people who also want to see the repository use nostr could use this and accept that the number of other contributors / maintainers who see it might be lower.
to achieve this the nip34 spec would need to be tweaked so that it is not assumed that the author is a maintainer if the maintainers parameter is present.