Preheat large non-stick skillet on medium - high heat and add turkey. Cook for 5 - 7 minutes, stirring occasionally and breaking into pieces.Transfer turkey to a large slow cooker along with tomato sauce, beans, corn, water, onion powder, taco seasoning and stir. Cover and cook on Low for 7 - 8 hours or on High for 3 - 4 hours. Garnish with desired toppings and serve hot.