Melt butter in the microwave or on the stovetop. Stir in the honey, Dijon mustard, olive oil, and lemon juice. Season with salt and pepper to taste. Transfer about half of the honey mustard mixture to a separate bowl for later.
Pound down the chicken for a more even thickness, about 1 inch thick. Brush both sides of the chicken with honey mustard glaze and then place it inside a lightly sprayed air fryer basket.
Cook at 380°F/193°C for 11-12 minutes, flipping at the halfway point.
For the best results: All air fryers are different, as well as the size of your chicken, because of this check on the chicken every 3-4 minutes of cooking and adjust as needed. Pull the chicken out once it reaches about 160°F/71°C and tent it in tinfoil to finish cooking and reach an internal temp of 165°F/74°C.