1Heat oven to 400°F. Spray 13x9-inch (3-quart) baking dish with cooking spray. Spread spaghetti evenly in dish; set aside.
2In 12-inch nonstick skillet, cook chicken broth, cream cheese spread, salt and pepper over medium heat 6 to 8 minutes, stirring occasionally, until cheese is melted. Stir in chicken. Remove from heat. Stir in frozen broccoli until well blended.
3Pour chicken mixture over spaghetti in baking dish (dish will be full). Cover tightly with foil. Bake 30 to 35 minutes, stirring well halfway through bake time, until spaghetti is tender. Stir before serving.