If you watch m2k vs ally videos m2k mixes up two options primarily. The neutral position is camping dairs up and in front of snake. After he does a few dairs m2k will either tornado the top of the shield for shield pressure/poke or airdodge behind snake and grab him. I think it's very important for mk's to know this about the matchup.
Also, if the snake sdis up and pulls a nade, the MK can just go to the side before the nade falls back into the nado, I think. This gets snake out, but I don't think it always forces a trade. Depending on how much duration is left in the nado, MK can still just retreat back to neutral as snake sdis out and pulls a nade. Then you go back to neutral postion of camping dairs until you either go for an air dodge to grab or nado shield poke.