Cook pasta as directed on package, omitting salt. Meanwhile, brown sausage in large deep skillet on medium-high heat, stirring occasionally to break up sausage. Drain; return sausage to skillet. Stir in zucchini, peppers and pizza sauce; cook 5 to 6 min. or until vegetables are crisp-tender, stirring occasionally.
Drain pasta. Add to sausage mixture with VELVEETA; mix lightly. Spoon into 13×9-inch baking dish sprayed with cooking spray; top with Parmesan.