This is one of my favorite RE synths. I have hours of fun importing patches from RYMCast
The Genesis/YM2612 is a different beast than what you find in other game systems, so I never really classify it first under "chip tunes." The RYM2612 is an FM synthesizer and it's unique. Of course with the history of the YM2612 being used in the Genesis, and with the innovative use of RYMCast for listening to Genesis songs and importing patches, sure it's easy to be inspired towards making that type of music. But it certainly doesn't have to be used for the "chip tune" genre anymore than other FM or subtractive synths can be.