Crush cornflakes until fine. Mix with garlic powder, salt, paprika, black pepper, and oregano.
Pound chicken slightly for even thickness.
Whisk egg and egg whites together in a bowl.
Dip chicken into egg mixture, then coat in seasoned cornflakes. Repeat for a second coating.
Place on a parchment lined air fryer rack. Air fry at 425 degrees F for about 12 minutes, until golden and cooked through.
Meanwhile, combine tomato passata and sauce seasonings in a saucepan. Simmer over medium heat for 5 minutes.
Top cooked chicken with sauce, mozzarella, and turkey pepperoni.
Return to air fryer for 2 minutes until cheese melts.
Optional: Broil on high for 2 to 5 minutes until bubbly and crispy.