I just published a plugin that allow to add webchat to Peertube video’s!
You need either a custom external webchat application that will be integrated in an iframe, or… juste a XMPP server with BOSH or Websocket, and anonymous login enabled! (sample config file provided!)
Everything you need to now is here: https://github.com/JohnXLivingston/peertube-plugin-livechat
There is a demo there: https://www.yiny.org/videos/watch/399a8d13-d4cf-4ef2-b843-98530a8ccbae
Enjoy!