1. Heat a Dutch oven over medium-high heat. Coat pan with cooking spray. Add onion, mushrooms, and garlic to pan; sauté 5 minutes or until liquid evaporates, stirring occasionally. Reduce heat to medium; add butter to mushroom mixture, stirring until butter melts. Sprinkle mushroom mixture with flour; cook 2 minutes, stirring occasionally. Gradually add milk and broth, stirring constantly with a whisk; bring to a boil. Reduce heat to medium-low; cook 10 minutes or until slightly thick, stirring constantly. Add pasta to pan; cook 10 minutes. Add cheese to pan, and stir until cheese melts. Add chicken and remaining ingredients to pan; cook 5 minutes or until broccoli is tender and soup is thoroughly heated.