Preheat Air Fryer on 370 for about 3 minutes.Spray pan lightly with vegetable oil.Place 1 soft taco shell in pan.Place shredded cheese on shell. (you can use as much or as little as you'd like.)Lay out fajita chicken strips so they are in a single layer.Put your onions and green peppers on top of your chicken.Add more shredded cheese.Place another soft taco shell on top and spray lightly with vegetable oil. ( I put the rack that came with the air fryer on top of the shell to hold it in place. If you don't, the fan will suck it up.)Set timer for 4 minutes.Flip over carefully with large spatula.Spray lightly with vegetable oil and place rack on top of shell to hold it in place.Set timer for 4 minutes.If it's not crispy enough for you, leave in for a couple of extra minutes.Remove and cut into 4 slices or 6 slices.Serve with Salsa and sour cream if desired.Enjoy!