I'm not an expert in this area, but I've already struggled against chatbots on Nostr, time-to-time. Annoying job, the smarter ones periodically change their npubs. Others use different npubs per relay they are listening on.

On the other hand there are really good AI bots regarding their knowledge. Proably - this is my conteo - some devs are testing, and Nostr users are the "lab rats".