Preheat your air fryer to 380°F (190°C) for about 3-5 minutes.
Slice the chicken breasts into thin strips.
Slice the yellow, green, and red bell peppers, as well as the red onion.
In a large bowl, combine the avocado oil, fajita seasoning, and salt. Add the chicken and vegetables.
Toss until evenly coated.
Place the seasoned chicken and vegetables in the air fryer basket, spreading them out into a single layer.
Cook in the air fryer at 380°F (190°C) for 11 minutes.
After 11 minutes, carefully remove the basket and shake it or use tongs to turn the chicken and vegetables.
Return the basket to the air fryer and cook for an additional 11 minutes, or until the chicken is cooked through and the vegetables are tender and slightly charred.
Once cooked, remove the chicken fajitas from the air fryer and serve immediately with warm tortillas, cheese, salsa, pico de gallo, guacamole, sour cream, and any other desired toppings.