Pound each chicken breast between two sheets of plastic wrap to a uniform ¾-inch thickness using a meat mallet or rolling pin.
Preheat air fryer to 400°F (200°C) for 3 minutes.
Mix lemon pepper seasoning, garlic powder, salt, and lemon zest in a small bowl. Coat breasts on all sides with olive oil, then press the seasoning mixture firmly onto both sides.
Place breasts in a single layer in the air fryer basket. Cook at 400°F for 9 minutes.
Flip each breast and cook 8–9 more minutes until an instant-read thermometer reads 165°F at the thickest point.
Rest on a cutting board for 5 minutes before slicing. Internal temperature will rise 3–5°F during resting.