Preheat the air fryer to 390°F for 3 minutes if the appliance instructions recommend preheating. Lightly coat the basket or crisper plate with cooking spray.
Pat the chicken dry. Pound any thick areas gently until every cutlet is about 1/2 inch thick, then season both sides with salt and pepper.
Place the flour in one shallow bowl. Whisk the egg and water in a second bowl. Mix the panko, 1/2 cup Parmesan, Italian seasoning and garlic powder in a third bowl.
Coat each cutlet lightly in flour, dip it in egg and press both sides into the panko mixture. Mist both sides with oil until the crumbs look lightly damp.
Arrange the cutlets in a single layer. Air-fry at 390°F for 7 minutes. Turn, mist any pale patches and cook for 2 to 4 minutes longer. Work in batches if necessary.
Top each cutlet with about 2 tablespoons warm marinara, 1 ounce mozzarella and a little Parmesan. Cook for 2 to 3 minutes longer, until the cheese bubbles and the thickest part of the chicken reaches 165°F.
Rest for 2 minutes. Garnish with basil or parsley and serve extra warm marinara at the table.
