Spray a slow cooker with nonstick cooking spray.
Place frozen meatballs in the slow cooker and top with drained pineapple (reserve the juice and set aside), green pepper and red pepper.
In a mixing bowl, whisk together pineapple juice, brown sugar, cornstarch, vinegar and soy sauce.
Pour sauce in slow cooker and mix everything to combine.
Cover and cook on low for 3-4 hours or until heated through.
Serve over cooked rice.
