Place the chicken breasts on a cutting board and cover them with a sheet of plastic wrap. Gently pound them with a meat mallet, rolling pin, or your hand until they are an even thickness throughout.
To dry brine, sprinkle kosher salt evenly over the chicken breasts and place them uncovered on a plate in the refrigerator for 30 minutes to 24 hours. Skip this step if you are not brining.
Remove the chicken from the refrigerator and allow it to sit at room temperature for about 15 minutes before cooking.
In a small bowl, mix together the paprika, garlic powder, onion powder, and black pepper. If you skipped the brining step, mix the salt directly into the spice blend.
Drizzle the chicken with olive oil and rub the spice blend evenly over both sides, ensuring full coverage.
Preheat your air fryer to 375°F. Once preheated, place the chicken breasts in the basket, smooth side down.
Cook for 6 minutes, then gently turn the chicken over with tongs to cook the other side. Continue cooking for another 2 to 8 minutes, or until the internal temperature reaches between 155°F and 160°F.
Transfer the cooked chicken to a plate, cover it loosely with foil, and let it rest for 5 to 10 minutes before slicing. The carryover heat will bring it to a safe 165°F.
Slice and serve as desired.