Hey, there are numerous VST instruments, available free, which emulate the usually 8-bit sound devices present in gaming consoles such as the NES, and contemporary home microcomputers, such as the C64, Amiga etc. You can do a pretty convincing rendition of console music using these within most modern DAWs, and is a simple way to incorporate these sounds into other productions, or include in arrangements with more 'traditional' instrumentation,though if you are more of a purist, you could use a tracker to sequence your tunes.
Sega, for one, was pretty notorious for having some quite talented composers engaged for music in their games, and i believe there is much video game music which has musical validity equivalent to any other serious music, regardless of genre.
There is a pretty massive 'chiptune' community scattered across the web, heaps of info and resources freely available - this is largely the domain of middle aged nerds, who live on the web
Without citing specifics i suggest a search for 'chiptune VST' should yield enough to get you started, and keep going for a while. - good luck, have fun!