Cook the beef: In a large pot, heat olive oil over medium heat. Add the ground beef, onion, salt, and pepper. Cook until browned and drain any excess fat.
Make the soup base: Stir in the beef broth, pinto beans, diced tomatoes, tomato soup, chili powder, cumin, garlic powder, and oregano. Bring to a boil.
Add the pasta: Stir in rotini and cook uncovered for about 10 to 12 minutes, until pasta is tender.
Make the queso: In a small saucepan, melt butter over medium heat. Whisk in flour and salt, cooking for 1 minute. Slowly pour in the milk, whisking until thickened. Stir in the cheddar cheese until melted and smooth.
Combine: Pour the queso into the soup pot and stir to combine. Simmer 5 to 10 minutes to blend flavors.
Serve: Garnish with sour cream, shredded cheese, and Fritos corn chips.
Notes
Store up to 4 days in fridge or 2 months frozen. Reheat slowly with milk or broth added.