Cut the bell peppers into ½-inch slices and add them to the baking sheet.
Cut the onion into thin slices and add them to the baking sheet.
Cut the chicken into ½-inch to 1-inch thick slices and add them to the baking sheet.
Add the oil and fajita seasoning to the baking sheet. Toss with your hands until everything is well coated, then spread into an even layer. It’s okay if chicken pieces are on top of the vegetables.
Place in the oven and bake for 10 minutes. Remove from the oven, toss everything, and return to the oven for another 10 to 15 minutes, or until the chicken is cooked.
Remove from the oven and squeeze the juice of 1 lime over the fajitas. Heat the tortillas in the microwave in 30-second intervals until warmed.
Serve in the warmed tortillas and enjoy.
Notes
Store leftover chicken and vegetables in an airtight container in the refrigerator for up to 4 days.