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