Going with Deku on this one, quite handily too.
Deku is > 1.66 megatons by a lot so their AP is basically the same.
His win cons are Blackwhip with his way higher LS and a properly built up Fa Jin. With Danger Sense and his own Analytical Prediction, he can figure out Iron Man’s skill set and avoid basically all of it. Mass attacks like missiles can be blocked with Air Pressure attacks or his mobility with Blackwhip + Float.
Can Iron Man see through Smokescreen? I’m certain he has some kind of thermal vision.
So it’s mainly an aerial battle with Izuku getting closer to restrain and beat Tony down while dodging his missiles and beams. He can snipe back at him with Air Force (though they’re bigger in this key since he doesn’t have his gauntlets) to pressure him even from range, but ultimately Deku is all about getting in close for a kick. Probably will spend the fight dodging and flying around, swinging with Blackwhip to build up Fa Jin, then blitzing over to Iron Man with it to wrap him up and take him down.
Also, Deku’s mid-gauntlets can act like High 6-C shields, which let him just straight up block Iron Man’s rays if he wants to.