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