Add chocolate chips and butter in a heatproof bowl. Place them in the air fryer, heat it at 160OC for 1 min. After 20sec, pull out the tray and stir the mixture. Put the tray back and let it continue to heat. Repeat the same step at every 20s interval until the chocolate and butter is fully melted. #Tip: Heating the mixture longer may risk the chocolate getting burnt.