Heat oven to 350°F. Spray 11x7-inch (2-quart) glass baking dish with cooking spray. Cook and drain pasta as directed on package.
Meanwhile, in 3-quart saucepan, melt butter over medium heat. Add onion; cook 3 minutes, stirring occasionally. Stir in flour; cook and stir 30 seconds. Slowly stir in broth; heat to boiling. Cook 3 to 4 minutes, stirring frequently, until thickened. Remove from heat; stir in cheese. Gently stir in cooked pasta, chicken, artichoke hearts, tomatoes, olives and parsley. Spoon into baking dish.
Bake uncovered 25 to 30 minutes or until hot. Garnish with additional fresh parsley if desired.