In the rich text editor:
@NyarthKing
In a comment:
[NyarthKing](https://chowlings.com/user/NyarthKing)
For Names and Avatars:
In the rich text editor:
%NyarthKing
In a comment:
[](https://chowlings.com/user/NyarthKing) [NyarthKing](https://chowlings.com/user/NyarthKing)