Follow these simple steps to create your Sheet Pan Chicken Fajitas:

1. Preheat the Oven: Preheat your oven to 400°F (200°C).
2. Prepare the Chicken and Veggies: In a large bowl, combine the sliced chicken, bell peppers, and onion.
3. Season: Add olive oil, chili powder, cumin, garlic powder, smoked paprika, salt, and pepper to the bowl. Toss until everything is evenly coated.
4. Spread on Sheet Pan: Line a baking sheet with parchment paper for easier cleanup. Spread the chicken and vegetable mixture evenly across the sheet pan.
5. Bake: Place the sheet pan in the preheated oven and bake for 20 minutes, or until the chicken is cooked through and the vegetables are tender.
6. Toss Midway: Halfway through the baking time, stir the mixture for even cooking.
7. Warm Tortillas: While the fajitas are baking, warm the tortillas in a dry skillet or microwave.
8. Serve: Remove the pan from the oven and garnish with fresh cilantro if desired.

These straightforward instructions ensure that even novice cooks can achieve delicious results with minimal effort.