Cool! I was thinking about writing a chess game for this Octojam, but when I looked into the AI part I quickly realised that that's a bit too much for me to do in a couple of days or so. So no chess game for me this year.
I did however design these four colour hires chess pieces. Board is 64x64 pixels, squares are 8x8. So yeah, same here, if anyone feels like using these, go ahead :) An acknowledgement of my work would be appreciated, but otherwise feel free to do as you please.