Knight

Nf5 to block the pass pawn. Also attacking e6 and g6 pawn.

Nf1 (or f3) to protect the pawn on h2 from the Black Queen and Bishop.

Nd4 would centralize the knight.

d6 is a hole. By placing the knight to d6, the knight can really do damage in the enemy territory.

To stop the black knight from blocking our Pawn from queening, white needs to find a way to put the black knight to prison, Bd5. Can you see why this might cause some discomfort for black knight?