"chipmusic/chiptune/micromusic" is really a genre?, my anwser is no. Why?, "chipmusic/chiptune/micromusic" is more a tool/instrument. Same happend with pixel art, it's not actually art is just a tool that kind of result....
Why i think that, well... there are plenty "chipmusic" which is actually more than that. Some people sing, play string instruments, play drums, play piano, etc, etc... over a simple/complex melody composed or created with an old hardware or new but reminding the basic sounds from the simple wave forms such as, square, triangle, sin, saw, noise, etc etc.... but this is more complex as linde saids... and since that.... this is getting more into the stupid/deep of concepts... so i will stop here...
Just call it according to what rhythm you use.
In my personal experience, i do.... pop/hip-hop/dnb/glich/vgm/breakcore with NES/Gameboy sound mostly, or kind of... not sure about that actually...