Should I use parting shot or you turn for a vgc regulation f incineroar?
I would suggest Parting Shot like the earlier comments, lowering your opponent's SpA and Atk while switching out is better then just doing chip damage, plus Incineroar is quite slow even with full EVs in Speed
Even Smogon's preferred VGC set uses Parting Shot.
so overall Parting Shot is more competitively viable then U-Turn.