Bone and skin chicken and cut into 1" squares. In a food processor, combine onions, thyme, sugar, pepper, salt, nutmeg and allspice and blend to form a paste. Transfer to a shallow dish. Place chicken in the marinade and turn to coat. Cover and marinate in the refrigerator for at least 8 hours, turning occasionally. In a large nonstick skillet, heat oil over medium high heat. Add the chicken and saute for 4-6 minutes or until done. Thread onto skewers and serve. Can also be skewered and then cooked on a grill.