Add the black beans, broth, diced tomatoes with green chiles, onion, and garlic to your slow cooker.
Stir in the cumin, chili powder, oregano, salt, and black pepper until well combined.
Cover and cook on low for 7 hours or on high for 4 hours until the flavors have melded together.
Use an immersion blender to partially blend the soup for a creamier texture, or mash some beans against the side of the slow cooker with a spoon.
Stir in the lime juice just before serving and adjust seasoning to taste.
Serve hot with your favorite toppings like shredded cheese, sour cream, avocado, and tortilla strips.