1. Place chicken in a large resealable plastic bag set in a shallow dish. Add cilantro, ginger, garlic, serrano pepper, oil, coriander, cumin, salt, garam masala (if desired), and nutmeg to bag. Seal bag. Turn and press bag to coat chicken. Chill for at least 2 hours or up to 6 hours.
2. On eight 10- to 12-inch skewers, alternately thread the chicken, pineapple, red sweet pepper, and green sweet pepper, leaving a 1/4-inch space between pieces.
3. Place kabobs on the rack of an uncovered grill directly over medium coals. Grill for 8 to 12 minutes or until chicken is no longer pink, turning occasionally to brown evenly. Makes 4 (2-skewer) servings.
Broiler Directions:Preheat broiler. Place kabobs on the unheated rack of a broiler pan. Broil 4 to 5 inches from the heat for 8 to 12 minutes or until chicken is no longer pink, turning occasionally to brown evenly.
*Note:Because chile peppers contain volatile oils that can burn your skin and eyes, avoid direct contact with them as much as possible. When working with chile peppers, wear plastic or rubber gloves. If your bare hands do touch the peppers, wash your hands and nails well with soap and warm water.