Set your oven to 400°F (200°C) and line your sheet pan with parchment paper or a silicone mat for easy cleanup.
Slice the bell pepper and onion into thin strips, about ¼-inch thick. Cut the chicken breasts into thin strips to match the size of the veggies for even cooking.
In a large bowl, combine the olive oil, chili powder, cumin, garlic powder, onion powder, salt, and pepper. Toss the chicken strips, bell pepper, and onion in the seasoning mixture until everything is evenly coated.
Arrange the chicken and vegetables in a single layer on the prepared sheet pan. Avoid overcrowding to ensure they roast instead of steam.
Place the sheet pan in the oven and roast for 20-25 minutes, flipping the chicken and veggies halfway through to ensure even browning. The chicken should reach 165°F internally when done.
While the chicken and veggies roast, warm your whole wheat tortillas in a dry skillet or microwave wrapped in a damp towel. This makes them pliable and easier to wrap.
Spoon the roasted chicken and peppers onto each tortilla. Garnish with fresh cilantro and a squeeze of lime juice for a bright, fresh finish. Roll up the tortilla tightly to form a wrap.
Serve your Sheet-Pan Fajita Chicken & Peppers Wraps immediately, accompanied by extra lime wedges on the side.