In 2-quart saucepan, heat 3 cups water to boiling. Stir in pasta (from Chicken Helper box). Return to boiling; reduce heat. Simmer uncovered about 10 minutes, stirring occasionally, until pasta is tender. Drain; cover to keep warm.
Meanwhile, in 10-inch nonstick skillet, melt margarine over medium-high heat. Add mushrooms, onion and bell pepper; cook about 3 minutes, stirring occasionally, until vegetables are crisp-tender. Remove from skillet.
In same skillet, mix milk, sauce mix (from Chicken Helper box), Italian seasoning, paprika and ground red pepper. Heat to boiling, stirring occasionally.
Reduce heat. Cook uncovered 6 minutes, stirring occasionally. Stir in tomato pasta sauce, vegetables and chicken. Cook uncovered about 3 minutes longer or until thoroughly heated. Serve over pasta.