Outsmart him lol he's a pattern.
If MK dairs your shield, bair.
If MK SHnairs your shield, grab, or dash attack.
Pivot grab a lot.
Use nades to beat tornado.
Use C4 to recover if it looks like he has a shot at even touching you.
Any time you dash attack a shield, dacus it.
Fair works, use it (sparingly).
Never jab, ever.
Chris, though being a cool guy, isn't that great of an MK. He relies on the fact that MK is absolutely busted, and beats you guys on that merit alone. Learn the match-up as much as possible, and you'll finally start ****** on him.
Top level MKs though... ugh. Funnily enough, Diddy can't even recover against an MK who knows wtf they're doing, lol.