Heat the olive oil in a large pot or Dutch oven over medium heat. Add the diced onion and sauté until translucent, about 5 minutes.
Stir in the minced garlic and diced bell pepper, cooking for another 3-4 minutes until softened.
Add the diced tomatoes, chicken or vegetable broth, black beans, cumin, chili powder, salt, and pepper. Bring the mixture to a boil, then reduce the heat and let it simmer for 20 minutes.
While the soup is simmering, preheat the oven to 375°F (190°C). Cut the corn tortillas into thin strips and spread them out on a baking sheet. Lightly spray or drizzle with olive oil and season with salt. Bake for about 10-12 minutes, or until crispy and golden.
After 20 minutes, add the corn kernels to the soup and continue to cook for another 5 minutes. Stir in the lime juice and chopped cilantro just before serving.
Ladle the soup into bowls and top with crispy tortilla strips, shredded cheese, and any of your desired toppings like avocado or sour cream.