Heat olive oil in a large pot over medium heat.
Add chopped onion and cook until translucent, about 5 minutes.
Add minced garlic and cook for another minute.
Add chopped red bell pepper and corn kernels, cook for 5 more minutes.
Stir in black beans, vegetable broth, diced tomatoes, ground cumin, chili powder, salt, and black pepper.
Bring to a boil, then reduce heat and let simmer for 20 minutes.
Use a blender to puree a portion of the soup for a thicker consistency, if desired.
Serve hot, garnished with avocado slices, lime wedges, chopped cilantro, and tortilla chips.