Pound the chicken breasts to an even ½-inch thickness. Place in a zip-top bag with the Italian dressing, garlic powder, onion powder, salt, and pepper. Refrigerate for at least 30 minutes (or overnight).
Preheat the air fryer to 375°F (190°C) for 3–5 minutes. Lightly spray the basket with olive oil.
Remove chicken from the marinade and pat thoroughly dry. Place in a single layer in the air fryer basket.
Air fry at 375°F for 10–12 minutes, flipping halfway through, until the internal temperature reaches 160°F.
While the chicken cooks, stir together the ranch dressing and ¼ cup Parmesan in a small bowl. In a second bowl, combine the panko, ⅓ cup Parmesan, melted butter, and garlic powder until the mixture resembles wet sand.
Open the air fryer. Spread the ranch-Parmesan mixture over each breast, top with provolone slices, then pile on the panko-Parmesan topping and gently press it down.
Air fry for another 3–4 minutes at 375°F, until the topping is deep golden brown and the cheese is fully melted (internal temp 165°F).
Let the chicken rest 3–5 minutes, garnish with fresh parsley, and serve immediately.