Hello. I'm playing COD4 on some servers. I have resetted my results there by a command.

Is it possible to reset my own stats on Gametracker or create a new account to start earning the points again without changing my nickname?

You'll need to contact the owners of the server (who ever has claimed the page). That person can reset stats individually, if they are willing to do it for you. If it is your server, you can get this done yourself as well.