Season the cubed chicken with salt and pepper. lightly dust with garlic powder and cayenne (to taste)
In a large skillet over med-hi heat brown and cook chicken in 2 Tbsp of olive oil.
While the chicken is cooking combine the pineapple juice, sugar, vinegar, ketchup, soy sauce, and salt in a small sauce pan over medium heat. Once it comes to a boil reduce the heat to keep it warm until the chicken is cooked through.
Put the pineapple, chopped bell pepper and onion in a 9x13 with the cooked chicken and top with the sweet n sour sauce.