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