1. Use paper towels to pat dry the diced chicken breasts. Place the chicken and vegetables in a large plastic zip-top bag.

2. To prepare the marinade, combine the lime juice, olive oil, chili powder, garlic powder, salt, and pepper in a bowl. Pour the marinade over the chicken and vegetables in the plastic bag. Close the bag, sealing out any excess air, and turn the bag to coat the chicken and vegetables with the marinade. Let the mixture marinate in the bag at room temperature for 30 minutes or in the refrigerator for 2 hours, turning the bag occasionally. Drain the chicken and vegetables, and reserve the marinade.

3. Thread the chicken and vegetables in an alternating fashion onto four long or eight short skewers, and season with salt and pepper. Place skewers on the grill rack directly over medium heat, and grill for 4 to 5 minutes. Turn skewers and brush them with some of the reserved marinade. Discard any remaining marinade. Grill 4 to 5 minutes more or until chicken is no longer pink (170°F) and vegetables are crisp-tender.

4. Serve skewers over rice, if desired.