Add-on Need help add-on to change users nick name!

[Jefferson Filho]

Hello guys, I would like to know if someone could help me to make a simplo add-on that can give the option to my users to change they nick names, because I came from IPB and all my users nick name now is they login names, I know there is a add-on already that does what I'm asking, but at moment I can't afford it, so I just want to make add-on that I cant set by group how many times they can chnage they nick names.

Thank you!