Marinating (optional): Place chicken tenders in a plastic zipper bag with the buttermilk and marinate in the refrigerator for at least 30 minutes, up to 2 hours.

When ready to cook, remove the chicken from the fridge and allow it to sit at room temperature for 15 minutes. 

Meanwhile, whisk together the egg and water in a large bowl until well combined. Transfer the chicken tenders to the bowl, then discard the marinade and bag.

Preheat the air fryer to 370 degrees F.

In a clean plastic zipper bag, add the flour, paprika, garlic powder, salt, pepper, and baking powder. Seal and shake well to combine. 

Working in batches of 3 to 4 at a time, remove the tenders from the egg, allowing excess to drop off, then place them in the bag with the flour. Seal and shake the bag to evenly coat the chicken. Remove the tenders to a plate, shaking off any excess flour, and repeat with the remaining pieces.

Lay the tenders in an even layer in the air fryer basket, working in batches as needed, so you don’t overcrowd them. Generously spray the tenders with cooking spray until the flour appears damp. 

Air fry the tenders for 15-20 minutes, flipping them once halfway through and spritzing them again with cooking spray. Continue cooking until the tenders are golden and 165 degrees F internally. (Exact cooking time will vary depending on the size of your tenders, your air fryer, etc.).