Preheat the oven to 400°F (200°C).
Make the dry spice mix: combine chili powder, garlic powder, cumin, paprika (if using), salt, and black pepper in a small bowl.
Prepare the chicken: place each chicken half flat on a cutting board and season both sides with the spice mix.
Assemble the roll-ups: place about 6 bell pepper slices (two of each color) across the center of each chicken piece, then tightly roll the chicken around the peppers and secure the seam with a toothpick.
Heat the oil in a large oven-safe skillet over medium-high heat. Add the chicken roll-ups seam-side down and cook 2–3 minutes per side, turning to brown all sides.
Transfer the skillet to the preheated oven (or move the rolls to a baking sheet if your pan is not oven-safe) and bake for 15 minutes, or until the chicken is cooked through and peppers are slightly charred.
Remove toothpicks, garnish with chopped cilantro and a squeeze of lime juice if desired, and serve with rice, tortillas, or vegetables.