Begin by preheating your oven to 425°F (220°C) to ensure it’s hot and ready for perfect roasting.
In a large mixing bowl, combine the thinly sliced chicken along with the red and green bell peppers and the yellow onion.
Drizzle the olive oil over the mixture, then add the fajita seasoning, lime juice, and a pinch of salt and pepper. Toss everything together thoroughly until all the ingredients are well coated in the oil and seasoning blend.
Transfer the chicken and vegetable mixture to a large sheet pan, spreading it out evenly to allow for even cooking.
Place the sheet pan in the preheated oven and bake for approximately 20 minutes. Halfway through cooking, give the mixture a gentle stir to ensure even roasting and browning. The chicken should be fully cooked and the vegetables tender by the end of the cooking time.
After baking, remove the sheet pan from the oven and allow it to rest for a couple of minutes. This helps the flavors meld together nicely.
To serve, spoon the warm chicken and vegetable mixture onto tortillas. Garnish generously with freshly chopped cilantro, and if you’d like, provide sour cream and avocado on the side for an extra creamy and rich addition.