01 - Preheat oven to 400°F. Lightly grease a baking dish with olive oil or nonstick spray.
02 - In a large bowl, toss the sliced bell peppers and onion with olive oil, chili powder, smoked paprika, cumin, garlic powder, onion powder, salt, and black pepper until evenly coated.
03 - Slice each chicken breast horizontally without cutting all the way through, creating a butterflied piece. Place between plastic wrap and pound to approximately 1/4-inch thickness using a meat mallet or rolling pin.
04 - Evenly divide the seasoned vegetable mixture and shredded Monterey Jack cheese among the flattened chicken cutlets. Lay the filling across the center of each piece, then roll up tightly and secure with toothpicks.
05 - Place the roll-ups seam-side down in the prepared baking dish. Sprinkle any remaining fajita seasoning over the top.
06 - Bake for 25–30 minutes until the chicken is cooked through (internal temperature reaches 165°F) and the cheese is bubbling and golden.
07 - Remove toothpicks, garnish with chopped fresh cilantro, and serve with lime wedges and sour cream on the side.