I helped design DID (well, a bit). It's perfectly possible for different systems to have different URI schemes, in fact, it's encouraged at internet scale, which is the path to interoperability

nostr already has decentralized identifiers. In fact they are more decentralized than DIDs because the canonicalization does not depend on an http context, or on external vocabs and schemas, including xml schemas

It would not be hard to give nostr a URI scheme, and I think it can be done by cherry picking the best parts of DID, and throwing out the bloat, the technical debt, external centralized dependencies and stuff that doesnt work, such as range of the did resolution function

nostr URI schemes can be simple, self-contained and truly decentralized, allowing internet scale interop

So far people are coalescing around nostr:npub.. type things, which I wasnt fond of at first, but is growing on me