Spray 13x9-inch glass baking dish with cooking spray. Place uncooked noodles in baking dish.
Heat large skillet over medium-high heat. Add beef; cook 5 to 7 minutes or until crumbled and no longer pink. Drain. Add vegetables, undrained tomatoes, enchilada sauce and water to skillet; stir. Bring to a boil. Pour mixture over noodles.
Cover dish tightly with foil; bake 15 minutes. Stir; sprinkle with cheese and cover with foil. Bake 10 minutes more or until noodles are tender. Sprinkle with green onions. Serve with sour cream, if desired.