Hey it's me.
I use Fl Studio 12 and a few different plugins including Magical 8-Bit Plugin, Retro Boy, ymVST, 3x Osc, ChipDrum, etc. to make 8-bit-sounding music. It's not faithful to what could have been produced on an old NES or anything, it's just something I make for fun.
If you have suggestions just post a comment on any of my videos and I'll get around to it.