Pat dry chicken breasts and preheat air fryer to 360°F (180°C).
Mix ranch seasoning, smoked paprika, garlic powder, salt, black pepper, and cayenne pepper; reserve 1 teaspoon.
Brush chicken with mayonnaise, sprinkle with seasoning, then add parmesan, pressing gently to adhere.
Place chicken in air fryer basket seasoned side down; repeat process on the other side. Mix reserved parmesan and seasoning for topping.
Cook at 365°F (185°C) for 8-9 minutes, flip, then sprinkle with reserved seasoning and parmesan. Cook at 375°F (190°C) for 7-8 minutes until internal temp reaches 165°F (73°C). Let rest 5 minutes before serving.
Notes
Ensure chicken is fully cooked and internal temperature reaches 165°F (73°C).