Preheat oven to 425 degrees F. Lightly oil a baking sheet or coat with nonstick spray.
Place chicken, bell peppers, onion and garlic in a single layer onto the prepared baking sheet. Stir in olive oil and chili powder mixture; gently toss to combine.
Place into oven and bake for 25 minutes, or until the chicken is completely cooked through and the vegetables are crisp-tender. Stir in cilantro and lime juice.
Serve immediately with tortillas.
For the chili powder mixture
In a small bowl, combine chili powder, cumin, oregano, paprika, 1 1/4 teaspoons salt and 1 1/4 teaspoons pepper.
Notes
Use a good quality sheet pan. A durable sheet pan is ideal – it will last for years with minimal wear and tear, and will help achieve even cooking and avoid warping at high temperatures.
Prep ahead of time. Save time by mixing the chili powder mixture in advance, and prepping and dicing the vegetables 1-2 days prior and storing them in airtight containers in the fridge.
Cut in uniform size. Cut all of the fajita ingredients in similar size pieces for quick, even cooking and a consistent bite throughout.
Add some heat. Add 1-2 jalapeños for a spicy kick of heat!
Make it vegetarian. Skip the chicken and add diced sweet potatoes, butternut squash or mushrooms.
Avoid an overcrowded pan. An overcrowded pan will steam the chicken instead. Use two sheet pans, if needed, ensuring that the ingredients do not overlap.
Repurpose leftovers. The leftovers make for excellent burrito bowls and salads.
Reheat in the oven. Leftover chicken can be rubbery when reheated in the microwave. For best results with leftovers, reheat in the oven at 325°F, covered in aluminum foil until warmed through.
Freeze before baking. Store the vegetables and chicken in separate freezer bags for flexibility, discarding any excess liquid from the peppers prior to baking. Label, date and freeze up to 3 months.