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