Slice the chicken breasts, bell peppers, and onion into thin strips.
In a large bowl, toss the chicken, peppers, and onions with olive oil and taco seasoning until evenly coated.
Add the mixture to your air fryer basket in an even layer (work in batches if needed). Cook at 400°F for 15–20 minutes, shaking or tossing every 5 minutes to ensure even cooking. You can also bake in the oven (see blog post)
The chicken should be fully cooked (internal temperature of 165°F) and the vegetables tender with slightly crispy edges.
Load into warm tortillas and top with Greek yogurt, cheese, and salsa—or serve as a bowl or salad.
Notes
You can also bake the fajitas on a sheet pan in the oven (see instructions in blog).
If you're worried about the chicken being cooked through, make sure you are tossing it every 5 minutes while it's air frying, then double check with a meat thermometer.