The Ki-43 would have had to have been substantially strengthened to conduct carrier operations.
Most certainly, but instead of just modifying the Ki-43, a new design incorporating the type's features would seem more plausible, perhaps utilising the same basis of the Type 9-Shi fighter, as with what the A5M was to the A6M? The aircraft has to meet the stringent requirements of the 12-Shi spec. The Ki-43 alone would not have done so.