Heat 1 tablespoon olive oil in a medium skillet pan over medium heat. Add the onion and cook for 3-4 minutes, stirring occasionally.
Add the ground beef, sprinkle with 1 teaspoon salt, garlic powder, cumin, chili powder, and paprika. Cook until browned and no longer pink. Drain any excess grease.
To a 6-quart slow cooker, add the cooked onion and ground beef, black beans, pinto beans, tomato sauce, diced tomatoes, green chili, corn, and stock, stirring until well combined.
Cover and cook on high for 4-5 hours or low for 7-8 hours.
Uncover and add the lime juice, stirring to combine. Taste and add additional salt or lime juice if desired. Serve with toppings of your choice.
Stovetop Instructions
Heat a large pot or Dutch oven over medium heat. Add the onion and cook for 3-4 minutes, stirring occasionally.
Add the ground beef, sprinkle with 1 teaspoon salt, garlic powder, cumin, chili powder, and paprika. Cook until browned and no longer pink. Drain any excess grease.
Add the black beans, pinto beans, tomato sauce, diced tomatoes, green chili, corn, and stock, stirring until well combined.
Cover, bring to a boil, then reduce to a simmer. Cook, covered, for 20-25 minutes.
Uncover and add the lime juice, stirring to combine. Taste and add additional salt or lime juice if desired. Serve with toppings of your choice.
Notes
I prefer 90/10 lean ground beef so the soup doesn't end up with a layer of grease on top, but if I only have 80/20 I just drain it well after browning; but both work.