I've maintained that the word "nerd" has been thrown about wrongly for a while now. Somehow it became cool to be a nerd. By definition:
1. A foolish or contemptible person who lacks social skills or is boringly studious: "one of those nerds who never asked a girl to dance".
2. An intelligent, single-minded expert in a particular technical discipline or profession.
It has next to nothing to do with video games. Just so happens that nerds, generally speaking, enjoy video games. But it's not a two-way relationship, not all gamers are nerds. Felicia Day happens to be a nerd [you can't be a mathematician and not be a nerd], and a gamer and famous though.