Preheat the air fryer at 360F°.
Combine breadcrumbs and parmesan cheese in a bowl. Melt the butter in another bowl.
Lightly brush the butter onto the chicken, then dip into breadcrumb mixture.
When the air fryer is ready, place 2 pieces in the basket and spray the top with oil.
Cook 6 minutes, turn and top each with 2 tbsp sauce and 1 1/2 tbsp of shredded mozzarella cheese.
Cook 3 more minutes or until cheese is melted.
Set aside and keep warm, repeat with the remaining 2 pieces.