Preheat the oven to 375°F. Line a baking tray with parchment paper or lightly grease.
In a large mixing bowl, add diced chicken, olive oil, salt, pepper, paprika, garlic powder, onion powder, chili powder, oregano, and cumin. Mix until well combined. Add garlic, bell peppers, and onion. Mix until the chicken, peppers, and onions are evenly coated.
To the sheet pan, add the chicken mixture and spread evenly in a single layer.
Bake for 30-35 minutes or until the chicken is fully cooked (chicken should reach 165°F on a thermometer) and starts to brown.
Warm tortillas by wrapping them in a damp paper towel in the microwave for 30 seconds. Or warm tortillas directly on the electric or gas element on medium heat. Flip with tongs until lightly browned and warmed through.
Serve fajita mixture on warmed flour tortillas. Top with your favorite toppings and garnish.
Notes
Place the sheet pan under the broiler for a minute or two until the veggies start charring on the edges.
Be sure chicken is cooked to an internal temperature of 165°F for safe consumption.
Use 2 sheet pans if necessary to ensure it does not get over crowded.
Refrigerate leftovers in a covered container for up to 3 days. Portions can be frozen in zippered bags for up to one month.