there was a project https://blog.torproject.org/tor-messenger-beta-chat-over-tor...
but I don't know what the status is, quick google searches make it seem abandoned
Ricochet was a big inspiration for my project Quiet.[3]
Cwtch also deserves a mention, though it depends on ephemeral servers and isn't fully p2p. Briar is another and frequently comes up on HN. [4][5]
1. https://en.wikipedia.org/wiki/Ricochet_(software)