In a medium saucepan, combine onion, sweet pepper, mushrooms, zucchini, and 1/4 cup of the broth. Bring to boiling; reduce heat. Simmer, covered, for 5 minutes.
Stir in the remaining broth, the undrained tomatoes, pizza sauce, sausage, and seasoning. Simmer for 5 to 10 minutes more or until the vegetables are tender. Top each serving with cheese. Makes 6 servings.