play a match on a server with ns2stats activated and change your nickname on the server too. your nickname should appear now on ns2stats.org
background: ns2stats receives match data like your steam id and used nickname. if you change your nickname the new nickname is added to ns2stats automatically because your steamid is the same.
No, I think ns2stats automatically register the various names you use in game. You don't need to change it while in game. If you want a specific name to appear on your player profile, just use this name while playing. You define your username in the option of with the name command.
Comments
your nickname should appear now on ns2stats.org
background:
ns2stats receives match data like your steam id and used nickname. if you change your nickname
the new nickname is added to ns2stats automatically because your steamid is the same.