In a large pot, heat the olive oil over medium heat. Add the diced onion and cook until softened, about 5 minutes. Stir in the minced garlic and cook for an additional minute until fragrant.
Add the red bell pepper, cumin, chili powder, smoked paprika, and cayenne pepper (if using). Cook for another 3-4 minutes, stirring occasionally.
Pour in the chicken broth and bring to a simmer. Add the shredded chicken, sweet corn, black beans, and diced tomatoes. Stir well and let the chowder simmer for about 15 minutes.
Reduce the heat to low and stir in the heavy cream. Allow the chowder to heat through for another 5 minutes, but do not let it boil.
Stir in the chopped cilantro, lime juice, and season with salt and pepper to taste.
Serve hot, garnished with diced avocado and crumbled queso fresco.