Mix the smoked paprika, black pepper, garlic powder, onion powder, oregano, cayenne pepper, salt, buttermilk, and egg in a large bowl.
Place chicken in the bowl and mix until all of the chicken is covered. Place a piece of plastic wrap directly on the surface of the chicken. Marinate in the fridge for at least 30 minutes, preferably 2 hours.
Preheat your air-fryer to 300°F. Mix flour, cornstarch, baking powder, salt, onion powder, and garlic powder in a large bowl. Remove one piece of chicken from the brine, shake off the excess brine, and dredge it in the flour mixture. Set it aside and repeat with the remaining pieces of chicken.
Spray cooking oil in your air fryer basket until it is completely covered. Place the chicken in the basket in a single layer, making sure no pieces overlap. Spray the top of the chicken with cooking oil until thoroughly covered. Cook for 20 minutes at 300°F.
Carefully flip the chicken pieces so as not to destroy the crust. Spray the top surface of the chicken again with cooking oil until thoroughly covered.
Cook for 15 to 20 minutes at 400°F, or until chicken skin is crispy and golden and the internal temperature is 160°F. Insert the thermometer in the thickest part of the chicken without touching the bone. Then try not to eat that crispy skin before serving. Forgive yourself if you fail miserably!
*I butchered a whole 3-pound chicken into 10 pieces, but feel free to use 3 pounds of whatever pre-cut chicken you desire, thighs, breasts, wings, etc. If your air fryer basket is small, it's best to fry similar-sized pieces in batches.**You can make your own buttermilk by mixing 1 cup of whole milk with 1 tablespoon of distilled white vinegar.***You need oil to fry chicken, even in an air fryer. If you don't have oil spray, put corn oil or vegetable oil in a spray bottle and use that.
Feel free to swap the spices used in the brine mixture with three tablespoons of your favorite spice blend.
A Note on the Cooking Time: Your cook time depends on the cuts of chicken used. The thicker the cut, the longer it takes to reach the required 165°F. Use a thermometer and pull the chicken once it hits 160°F. It will continue to cook outside of the air-fryer, and the temperature will reach 165°F. If you do not have a thermometer, cook the chicken until the juices run clear.