Based on https://github.com/MennoMax/gift add a docked chat in Godot Editor
Copy "TwitchChat" folder in your "res://addons/"(maybe you need to create it) folder.
Add a "auth.txt" file in your "res://addons/TwitchChat" folder.
In it :
YourName
TwitchToken
ChannelName
To obtain twitch token https://twitchtokengenerator.com/
Because I have single screen. Before I was need to switch between Godot Editor and Chat, or reduce godot to see chat. Now I can see chat and have Godot Editor in full-screen.