Prep the chicken: Pat the chicken dry with paper towels. If using breasts, pound them to an even thickness for even cooking.
Season: In a small bowl, mix smoked paprika, garlic powder, onion powder, salt, and pepper. Rub the chicken with olive oil, then sprinkle on the seasoning mix to coat evenly.
Preheat the air fryer: Set to 375°F (190°C) for 3–5 minutes.
Lightly oil or spray the basket to prevent sticking.
First cook: Arrange chicken in a single layer with space between pieces. Air fry for 8–10 minutes for thighs or 9–11 minutes for breasts, depending on thickness.
Sauce it: In a small bowl, stir BBQ sauce with brown sugar and a splash of apple cider vinegar or lemon juice if using. Brush sauce generously on the top side of the chicken.
Flip and sauce: Flip the chicken, brush the other side with sauce, and cook another 5–7 minutes.
The sauce should start to caramelize and get glossy.
Final glaze: Brush on a little more sauce and air fry 1–2 more minutes to set the glaze without burning.
Check doneness: The thickest part should reach an internal temperature of 165°F (74°C). If not, cook 1–2 minutes more and check again.
Rest and serve: Let the chicken rest 3–5 minutes. Add an extra swipe of BBQ sauce if you like, then serve with your favorite sides.