PREHEAT oven to 375°. Spray 8-inch square baking dish with no-stick cooking spray; set aside. Brown ground beef with onion in large nonstick skillet over medium-high heat, about 5 minutes.
STIR in 2 cups water, Knorr® Rice Sides™ - Beef flavor and red pepper and cook according to package directions, stirring in zucchini during last 2 minutes of cook time. Remove from heat; stir in all but 1/2 cup enchilada sauce.
ARRANGE 3 tortillas in baking dish, tearing 1 in half to cover bottom. Spread 1/2 of rice mixture over top, then top with 3 tortillas and remaining rice mixture. Top with remaining tortillas; spread with remaining 1/2 cup sauce and sprinkle with cheese.
BAKE 25 minutes until bubbly around edges. Let stand 10 minutes before serving.