Preheat Air Fryer to 400°F.
Using a sharp knife cut the chicken breasts into about 20 nuggets.
In a medium bowl, combine the chicken pieces and melted butter. Mix to evenly coat and then season with salt and pepper to taste.
In a second bowl, mix the panko, flour, salt, pepper, garlic powder, and cayenne pepper (if using).
Add 3 to 4 nuggets to the bowl with the panko mixture. Pess the nuggets into the coating on all sides until they're evenly covered. Transfer nuggets to a large plate or baking sheet and continue until the nuggets are the remaining chicken pieces.
Spray the nuggets on both sides with olive oil spray.
Spray or brush the air fryer basket with non-stick spray or olive oil.
Place the nuggets in the air fryer basket in a single layer. Cook in batches if necessary.
Cook for 8 minutes, flipping the nuggets halfway through.
Serve immediately with barbeque sauce and honey mustard for dipping.