Cook and stir peppers and onions in a large nonstick skillet sprayed with cooking spray on medium heat for 5 minutes. Add zucchini, cook and stir 2 minutes.

Stir in spaghetti sauce and cover. Cook 8 minutes, or until vegetables are crisp-tender, stirring occasionally.

Sprinkle with cheeses. Cook, covered, 1 minute or until cheese is melted.