In the rich text editor:
@NanaxChan
In a comment:
[NanaxChan](https://chowlings.com/user/NanaxChan)
For Names and Avatars:
In the rich text editor:
%NanaxChan
In a comment:
[![NanaxChan's Avatar](https://chowlings.com/images/avatars/295.jpg?v=1644063273)](https://chowlings.com/user/NanaxChan) [NanaxChan](https://chowlings.com/user/NanaxChan)