Place the ground beef and diced onion in a large stockpot over medium-high heat.
Cook and stir until the beef is thoroughly browned and onions are softened, approximately 8 minutes.
Drain any rendered fat from the pot.
Add the taco seasoning and ranch seasoning mix to the beef, stirring to coat.
Pour in the black beans, kidney beans, diced tomatoes with green chiles, corn, crushed tomatoes, and beef broth.
Stir to combine all ingredients and bring the soup to a gentle boil.
Reduce the heat to low and simmer for 15 minutes to allow flavors to meld.
Portion into six equal servings to maintain nutritional accuracy and serve.