Remove chicken from refrigerator 10-15 minutes before cooking. Pat dry with paper towels, then pound to even ¾-inch thickness using a meat mallet if needed.
In a small bowl, combine paprika, garlic powder, onion powder, oregano, brown sugar, salt, and pepper. Stir until the spice mixture is uniform and any clumps are broken up.
Brush olive oil all over both chicken breasts, covering all sides and edges. Sprinkle the spice mixture generously over the oiled chicken, pressing firmly into the surface. Flip and repeat on the other side.
Preheat air fryer to 375°F (190°C) for 3-5 minutes. Lightly spray the basket with cooking spray to prevent sticking.
Place seasoned chicken breasts in the air fryer basket in a single layer, not touching. Air fry at 375°F (190°C) for 10 minutes.
Open the air fryer and use tongs to carefully flip the chicken breasts over. Continue cooking for another 5-8 minutes, depending on the size of the breasts.
Check internal temperature in the thickest part with an instant-read thermometer. Remove chicken when it reaches 160°F (71°C) for juiciest results, or 165°F (74°C) for safe consumption.
Transfer chicken to a plate, tent loosely with foil, and rest for 5 minutes. Slice against the grain and serve immediately.