Begin by slicing the chicken breast into 3/4 inch chunks on a cutting board. Aim to produce 20-24 nuggets, depending on the chicken breast size.
Evenly distribute 1/4 tsp salt over the chicken pieces. Sprinkle the flour over the chicken and mix well to ensure each piece is thoroughly coated.
In a small bowl, combine the breadcrumbs, garlic powder, smoked paprika, and the remaining 1/2 tsp salt. Stir to blend the seasoning into the breadcrumbs. Pour the cooking oil over the breadcrumb mixture, stirring until it achieves a damp, sandy texture.
Pour the buttermilk into another small bowl.
Arrange the chicken, buttermilk, and breadcrumb mixture in a line. Using tongs or your hands, dip each chicken piece into the buttermilk, then roll it in the breadcrumb mixture until fully covered. Place the coated chicken pieces aside.
Preheat the air fryer to 400°F. Once heated, arrange the chicken nuggets in the air fryer basket in a single layer, avoiding overcrowding. If necessary, cook in two batches. Air fry for 8 minutes, flipping the nuggets halfway through.
Once done, remove the chicken nuggets from the air fryer and let them cool for 3-5 minutes. Serve with your favorite dipping sauce and enjoy.