Prepare the chicken: trim excess fat from chicken, then cut chicken breasts or thighs into 1 inch pieces.
Prepare the marinade: in a large bowl combine soy sauce, pineapple juice, brown sugar, olive oil, salt and black pepper. Stir to combine.
Add the chicken to the marinade, toss to coat, then cover and refrigerate for 1-2 hours.
If using bamboo skewers, soak the skewers in water while the chicken marinates.
Prepare the vegetables and pineapple by cutting them into bite-sized pieces.
Remove the chicken from the marinade. Optionally - sprinkle the chicken with your favorite poultry rub.
Preheat grill to medium-high heat.
Thread the chicken, peppers, onions, and pineapple onto wood or metal skewers, alternating between each of the ingredients.
Add kabobs to the pre-heated grill and grill for 15-20 minutes or until the internal temperature of the chicken is 165 degrees. Rotate the kabobs periodically so that all sides cook evenly.
During the last 5 minutes, brush the kabobs with your favorite BBQ sauce.