Combine turkey, pork, and next 5 ingredients (breadcrumbs through egg whites) in a bowl, and stir well. Shape mixture into 24 (1-inch) meatballs. Coat a large nonstick skillet with cooking spray, and place over medium-high heat until hot. Add meatballs, and cook 6 minutes, browning on all sides. Drain well. Wipe drippings from skillet with a paper towel.
Return meatballs to skillet. Add water, bouillon granules, and mushrooms; bring to a boil. Stir in noodles; cover, reduce heat, and simmer 10 minutes or until noodles are tender, stirring occasionally. Remove from heat; stir in sour cream. Sprinkle with green onions.