Set oven control to broil. Line 15x10-inch pan with sides with foil; spray foil lightly with cooking spray. Place bell pepper rings in pan. Top each with tomato and onion slice.
Place tilapia pieces next to vegetable stacks in pan. Sprinkle fish and vegetables with basil; spray lightly with cooking spray.
Broil 4 to 6 inches from heat 5 to 8 minutes or until fish flakes easily with fork. Serve fish with vegetable stacks.