In a small bowl, add in your melted butter, minced garlic, white miso paste, mirin, black pepper and honey. Whisk everything together until well combined.
Pour mixture over chicken thighs and mix well together to ensure all pieces of chicken are coated in the miso butter marinade. Let marinate for 20-30 minutes.
Set your Air Fryer to 400F and place chicken and all sauce mixture in the air fryer and let cook for 30 minutes, flipping half way through. Ensure that the internal temperature of the chicken reaches 165F.