Not really. Nostr DBs are a string or stringified json with some meta data, and a limited query language.

Solid is massively scalable, blazingly fast data storage, that is compatible with the existing web.

Both project bring something to the other. For nostr you get at least 1000x scalability. For Solid you get payments, portable identity, single sign-on and realtime updates.

It's a big win for the end user who doesnt need to know what is behind the scenes.