Preheat oven to 375°F and grease a large 9x13-inch baking dish, then cook macaroni according to package directions until al dente, drain, and set aside.
In a large pot or Dutch oven, brown ground beef with diced onion over medium-high heat, breaking up the meat as it cooks, then drain excess fat.
Add kidney beans, tomato sauce, diced tomatoes, chili powder, cumin, garlic powder, salt, and pepper to the beef mixture and simmer for 10 minutes, stirring occasionally.
Stir the cooked macaroni into the chili mixture until well combined.
Pour half of the chili mac mixture into the prepared baking dish and sprinkle with half of the combined cheeses.
Top with remaining chili mac mixture and sprinkle with remaining cheese.
Bake uncovered for 25-30 minutes until heated through and cheese is melted and golden brown on top.
Let stand for 5 minutes before serving with optional toppings like sour cream, green onions, or jalapeños.