Brown the ground beef: Place a large Dutch oven or stockpot over medium heat. Add the ground beef and chopped onion, breaking the meat into small crumbles as it cooks.

Cook until done: Continue cooking until the beef is fully browned and reaches an internal temperature of 160°F. Drain excess grease carefully.

Add the canned ingredients: Stir in the pinto beans, kidney beans, corn, diced tomatoes, tomatoes with green chilies, and Mexican-style tomatoes.

Season the soup: Add the taco seasoning and ranch dressing mix. Stir thoroughly to distribute the seasonings throughout the mixture.

Adjust the liquid: Add water or low-sodium beef broth as needed to achieve your preferred soup consistency. Start with a small amount and add more gradually.

Bring to a simmer: Heat until the mixture begins to bubble gently, then reduce the heat to low.

Let the flavors develop: Cover partially and simmer for about 30–45 minutes, stirring occasionally to prevent sticking.

Add optional olives: Stir in sliced black or green olives during the final few minutes if you enjoy their briny flavor.

Check the consistency: Add a splash of broth if the soup is too thick, or simmer uncovered briefly if it is too thin.

Serve warm: Ladle into bowls and offer shredded cheese, sour cream, sliced green onions, jalapeños, and corn chips as toppings.