In a large pot, bring salted water to a boil. Add the elbow macaroni and cook according to package instructions until al dente, about 8-10 minutes. Stir occasionally to prevent sticking.

Once cooked, drain the pasta in a colander and set aside. Do not rinse, as the starch helps the sauce adhere to the pasta.

In a large skillet, heat the olive oil over medium heat. Add the diced onion and sauté for about 3-4 minutes until translucent.

Add the minced garlic and cook for an additional 1 minute, stirring frequently to avoid burning.

Add the ground beef to the skillet. Cook until browned, breaking it apart with a wooden spoon, about 5-7 minutes. Drain excess fat if necessary.

Stir in the diced tomatoes, kidney beans, tomato sauce, chili powder, cumin, salt, and black pepper. Bring the mixture to a simmer and cook for about 10 minutes, allowing the flavors to meld.

Add the cooked macaroni to the chili sauce, stirring well to combine. Cook for an additional 2-3 minutes to heat through.

Remove from heat and sprinkle the shredded cheddar cheese on top. Cover the skillet for a few minutes to allow the cheese to melt.

Serve hot, garnished with additional cheese or chopped green onions if desired.