In a large skillet, cook beef over medium heat until no longer pink; drain. Sprinkle with salt and pepper. Stir in the pasta, tomatoes, broth, tomato sauce and Worcestershire sauce. Bring to a boil. Reduce heat; cover and simmer for 10-12 minutes.
Add squash and green pepper. Cook, uncovered, for 3-4 minutes or until pasta and vegetables are tender, stirring occasionally. Add 1/2 cup cheese; cook 1-2 minutes longer or until cheese is melted. Sprinkle with remaining cheese.