Slice each chicken breast horizontally to make 4 thin cutlets and season them with salt and pepper on both sides.
Set out three shallow bowls: season the flour with salt and pepper, beat the eggs until smooth, and mix the panko with Parmesan, oregano, red pepper flakes, and garlic powder.
Dredge each chicken piece in the flour, shake off any extra, then dip in the eggs, allowing excess to drip away, and finally press into the panko mixture to fully coat.
Place the breaded chicken in a single layer inside the air fryer basket (work in batches if needed) and cook at 400°F, flipping halfway through, for about 5 minutes on each side until cooked.
Spoon marinara sauce over each piece and sprinkle mozzarella cheese on top, then return to the air fryer for another 3 minutes until the cheese melts and browns lightly.
Garnish with chopped fresh parsley before serving for a fresh, colorful finish.