In the rich text editor:
@Nyadoggo
In a comment:
[Nyadoggo](https://chowlings.com/user/Nyadoggo)
For Names and Avatars:
In the rich text editor:
%Nyadoggo
In a comment:
[![Nyadoggo's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/Nyadoggo) [Nyadoggo](https://chowlings.com/user/Nyadoggo)