If your slow cooker has a sauté option, turn it on and heat the oil.
Add the onion and cook for about 5 minutes until softened.
Stir in the garlic and cook for 30 seconds until fragrant, then mix in chili powder, cumin, and smoked paprika, cooking for another 30 seconds.
Turn the sauté function off.
For slow cookers without a sauté function, sauté the onion in a separate pan, adding the garlic and spices as directed.
Transfer the mixture to the slow cooker base (optional but enhances flavor).
Add green chiles, tomatoes with their juices, vegetable broth, beans, and corn to the slow cooker.
Cover the slow cooker and set it to cook on high for 4 hours.
Once done, season the soup with salt and pepper to taste.
Stir in lime juice just before serving for a bright, tangy flavor.
Ladle the soup into bowls.
Garnish with your favorite toppings like shredded cheese, sour cream, cilantro, or tortilla chips, and serve.