In a bowl, combine pistachios, panko and herbs, then drizzle on butter and toss to distribute.
Pat lamb rack dry and rub over the pistachio mixture so the lamb is well coated.
Select Air Fry and adjust the temperature to 180°C and the time 18 minutes. Preheat Vortex until display indicates Add Food.
Add the lamb to the cooking basket and ignore when prompted to turn food.
When the program has finished, check the temperature with a meat thermometer to ensure that it is cooked to your liking (medium should be 54–57°C). Cook for additional 3 minutes intervals if you prefer it more well done.
Remove lamb rack from air fryer, cover with kitchen foil and leave to rest for at least five minutes before serving.