BROWN meat in large skillet sprayed with cooking spray; drain. Stir in salsa, zucchini and chili powder; simmer on low heat 10 min., stirring occasionally. Meanwhile, cook pasta as directed on package.
STIR corn and 1/2 cup cheese into meat mixture; cook 3 min. or until cheese is melted, stirring frequently.
DRAIN pasta; place in large bowl. Add meat mixture, lime juice and cilantro; mix lightly. Top with remaining cheese.