Cook macaroni according to package instructions. Drain, toss with the olive oil and set aside. Meanwhile, cook beef, onion and garlic in a large, nonstick skillet over medium-high heat, stirring occasionally, until beef is brown. Drain fat. Add the tomato sauce, chopped tomatoes, tomato paste and chili powder, and mix well to combine. Season with salt and pepper. Add macaroni and 1 1/2 cups of the cheese and mix well. Spoon mixture into a 9×13-inch baking pan; use one that can go directly from refrigerator to hot oven. Sprinkle remaining 1/2 cup cheese over macaroni. Cover with plastic wrap and chill. When ready to bake, preheat oven to 400 F. Remove plastic wrap and bake chili mac about 20 minutes until center is heated through. Broil top for 1 or 2 minutes until cheese is golden and bubbly. Watch carefully to prevent burning.