In a slow cooker turned to low, add all ingredients except for the meatballs and sour cream. Whisk the ingredients together and then add meatballs. Give the meatballs a good stir and cover. Cook for 6 hours on low. When the meatballs are warmed through, turn the crock pot to warm and add sour cream. Stir to combine and serve immediately. Serve as they are, over rice, noodles or potatoes.