Directions
Preheat your oven to 400°F (200°C). Line a large rimmed sheet pan with aluminum foil for easy cleanup.
Add the sliced chicken breast, bell peppers, and onion to the foil-lined sheet pan, spreading them out in an even layer.
Sprinkle the fajita or taco seasoning evenly over the chicken and vegetables. Use clean hands or tongs to toss everything together right on the pan until the chicken and veggies are well coated and the seasoning is evenly distributed.
Spread the mixture back into a single, even layer so the chicken strips and vegetables have a little space to roast rather than steam.
Bake for 18–22 minutes, stirring once halfway through, until the chicken is cooked through (no longer pink in the center) and the peppers and onions are tender with slightly charred edges.
If you like a bit more color, switch the oven to broil for 2–3 minutes at the end, watching closely so nothing burns.
Taste and sprinkle on a little extra fajita seasoning if you want a stronger flavor. Serve hot with warm tortillas and your favorite fajita toppings, if using.
Variations & Tips
If you like things spicy, use a hot fajita or taco seasoning blend, or add a pinch of crushed red pepper flakes when you toss everything together. You can swap the chicken breasts for chicken thighs if that’s what you have; just slice them thin so they cook in the same amount of time.
To keep it very budget-friendly, watch for bell peppers on sale and grab the cheaper bagged onions—they roast up beautifully. For a lighter option, skip the tortillas and serve the fajita mixture over chopped romaine or mixed greens as a warm salad.
If you’re into meal prep, double the recipe on two sheet pans and roast them at the same time, rotating the pans halfway through; the leftovers reheat well in a skillet or microwave. To make cleanup even easier on a hectic night, spray the foil lightly with cooking spray before adding the chicken and veggies so nothing sticks, then just crumple up the foil and toss it when you’re done.
