1 can (14-1/2 ounces) reduced-sodium chicken broth
1 cup fat-free milk
3 cups cubed cooked chicken breast
3 cups frozen chopped broccoli, thawed and drained
1 cup shredded reduced-fat cheddar cheese
Cook noodles according to package directions. Meanwhile, in a large nonstick saucepan over medium heat, cook onion in butter until tender. Stir in the flour, salt and pepper until blended. Gradually stir in broth and milk. Bring to a boil; cook and stir for 1-2 minutes or until thickened.
Remove from the heat. Drain noodles; place in a 2-qt. baking dish coated with cooking spray. Stir in 1 cup sauce. Layer with the chicken, broccoli and remaining sauce.
Cover and bake at 350° for 30 minutes. Uncover; sprinkle with cheese. Bake 5-10 minutes longer or until heated through and cheese is melted.