1To prepare marinade, combine first 3 ingredients in a shallow dish, and add chicken, turning to coat. Cover and chill 1 hour. Drain; discard marinade.
2To prepare spice mix, combine chili powder, cumin, salt, and black pepper in a small bowl. Rub 1 tablespoon spice mix over chicken. Combine remaining spice mix, onion, and bell peppers in a bowl, tossing to coat. Thread vegetables alternately onto 3 (12-inch) skewers. (if using bamboo, soak for 30 minutes in water)
4Place kebabs and chicken on a grill rack coated with cooking spray; grill 7 minutes on each side or until chicken is done and vegetables are tender.
5Remove the vegetables from skewers. Serve with chicken.