I’ll do a little more research for you, but  I believe you can add NostriChat by nostr:npub1l2vyh47mk2p0qlsku7hg0vn29faehy9hy34ygaclpn66ukqp3afqutajft 

There’s also a tool to add zaps but I’m forgetting the name of it. Maybe nostr:npub1lrnvvs6z78s9yjqxxr38uyqkmn34lsaxznnqgd877j4z2qej3j5s09qnw5 or nostr:npub1vp8fdcyejd4pqjyrjk9sgz68vuhq7pyvnzk8j0ehlljvwgp8n6eqsrnpsw can recall 

https://github.com/pablof7z/nostr-chat-widget