Prepare the Chicken: Place the chicken breasts on a cutting board and cover them with a large sheet of plastic wrap. Using a rolling pin, meat mallet, or your palm, lightly pound them into an even thickness.
Dry Brine (Optional): Place the chicken on a plate and sprinkle with kosher salt. Refrigerate uncovered for at least 30 minutes or up to 1 day. If you skip the dry brining, add the salt in the seasoning mix.
Season the Chicken: In a small bowl, mix together paprika, garlic powder, onion powder, and black pepper. Remove the chicken from the refrigerator and let it stand at room temperature for 15 minutes. Drizzle with olive oil, sprinkle with the spice mixture, and toss to coat evenly.
Air Fry the Chicken: Preheat the air fryer to 375°F (about 3 minutes for my model). Place the chicken, smooth side down, in the air fryer basket. Cook for 6 minutes.
Flip and Continue Cooking: Carefully flip the chicken over using tongs. Continue cooking until the internal temperature reaches between 155°F and 160°F, about 2 to 8 more minutes. Smaller breasts (around 6 ounces each) will need about 8 minutes total; larger ones may need 14 minutes or more. Check frequently towards the end to avoid overcooking.
Rest and Serve: Remove the chicken to a plate, cover, and let rest for 5 to 10 minutes. This allows carryover cooking to bring the chicken to a safe 165°F. Slice and enjoy!