Hitmonchan learns Mach Punch at level 16, but you can't get it from Tyrogue, so you'll need to go to the Move Relearner to get it.
It learns Vacuum Wave at level 26 but that's Special so won't be as powerful. You'd have to train to level 36 to get a good one, Sky Uppercut.
Or you can teach Drain Punch or Brick Break by TM. DP would be quite good, especially with leftovers since Hitmonchan has decent defense.