In large container with lid, or in large zip-top bag, mix together chicken, Mojo and pineapple juice until coated; transfer to refrigerator. Marinate chicken at least 2 hours, or up to 24 hours.
Strain chicken, discarding marinade. On 8 metal or pre-soaked wooden skewers, alternately thread pineapple, chicken, onions and peppers so that each skewer contains 3 chicken pieces.
Prepare grill to medium-high heat or heat grill pan over medium-high heat. Add chicken skewers to hot, greased grill grates. Cook, flipping skewers, until chicken is dark golden brown and cooked through and vegetables are tender, about 15 minutes. Transfer to serving platter; serve warm.