Slice each chicken breast horizontally into thin, even fillets for faster, more even cooking.
Pat the chicken dry with paper towels.
In a small bowl, combine paprika, smoked paprika, garlic powder, onion powder, salt, brown sugar, and cornstarch.
Place the chicken in a large bowl and sprinkle the seasoning mixture evenly over the chicken.
Add avocado oil and toss until every piece is well coated.
Preheat your air fryer to 415°F (213°C).
Arrange the chicken in a single layer in the basket, leaving space between each piece for proper airflow.
Cook the Air Fryer Chicken Breast for 10 minutes. Larger pieces may need 12–13 minutes.
Check that the thickest part reaches an internal temperature of 165°F (74°C).
Let the chicken rest for 5 minutes before slicing and serving.