Prepare the Marinade: In a large mixing bowl, whisk together the buttermilk, garlic powder, onion powder, smoked paprika, kosher salt, and black pepper until fully blended.
Marinate the Chicken: Submerge the chicken tenderloins in the buttermilk mixture, ensuring they are completely coated. Cover the bowl with plastic wrap and refrigerate for at least 1 hour; for the best flavor, marinate overnight.
Set Up the Breading Station: In two shallow dishes, pour the flour in one and the panko breadcrumbs in the other. This will create a simple assembly line for breading.
Coat the Chicken: Remove the chicken tenderloins from the buttermilk marinade, allowing any excess liquid to drip off.
Flour Dredging: Dip each chicken tender into the flour, pressing gently to ensure a good coating, then shake off any excess flour.
Second Dip: Return the floured tenders to the buttermilk mixture briefly, then roll them in the panko breadcrumbs, pressing the crumbs firmly to adhere.
Preheat the Air Fryer: Set your air fryer to preheat at 400°F (200°C) for about 5 minutes.
Arrange in Air Fryer: Lightly spray the air fryer basket with cooking spray. Place the chicken tenders in a single layer in the basket, ensuring they are not overlapping.
Final Spray: Give the tops of the chicken tenders a light mist with cooking spray or olive oil for a crispier finish.
Air Fry to Perfection: Cook the chicken tenders in the air fryer for 10-12 minutes. Flip them halfway through cooking to ensure even browning. The tenders should be golden brown and have an internal temperature of 165°F (75°C).
Rest and Serve: Carefully remove the chicken tenders from the air fryer and let them rest for a few minutes to lock in moisture before serving.