Step 1

Heat the oil in a large pot or Dutch oven medium heat until shimmering. Add the onion and cook, stirring occasionally, until softened, 3 to 4 minutes. Add the garlic, chili powder, cumin, smoked paprika, cayenne pepper (if using), and salt and cook, stirring often, about 1 minute more. Add the beef and cook, stirring and breaking apart the meat, until no longer pink, 3 to 5 minutes.

Step 2

Stir in the broth, tomato sauce, oregano, sugar, and macaroni and bring to a boil. Reduce the heat to low, cover, and simmer, stirring every so often so the macaroni doesn't stick to the bottom, until the pasta is al dente, 9 to 12 minutes. Use a soup spoon to skim any grease off the top, if necessary.

Step 3

Off the heat, add the evaporated milk and cheese and stir until the cheese is melted. Taste and adjust seasoning, if necessary. Ladle the chili mac into bowls and sprinkle with the scallions. Serve with more shredded cheese and tortilla chips.