Brown beef and onion in a 6-quart pot over medium-high heat for 8 minutes, breaking the beef into small crumbles and cooking it to 160°F. Drain excess fat.
Stir in garlic, chili powder, cumin, oregano and salt for 30 seconds.
Add diced tomatoes, tomato sauce, kidney beans and broth. Bring to a simmer and cook for 8 minutes.
Add macaroni and simmer uncovered for 8 to 10 minutes until tender, stirring often so it does not stick.
Divide among 6 bowls with plenty of broth around the solids. Add the measured cheddar evenly over the servings.