Sauté Aromatics: Warm the olive oil in a large pot over medium heat. Add the chopped onion, garlic, and jalapeño to the pot. Cook, stirring occasionally, until the onions become translucent and the jalapeño softens—about 5 minutes.
Season and Toast Spices: Sprinkle in the salt, black pepper, oregano, cumin, and chipotle chili powder. Stir thoroughly and cook for another 1 to 2 minutes, allowing the spices to toast and release their full aroma.
Add Tomatoes and Broth: Pour in the fire-roasted diced tomatoes with their juices and the chicken broth. Bring the mixture to a boil, then reduce the heat to low and let it gently simmer uncovered for 30 minutes. This simmering step helps deepen the flavors.
Blend Soup Base: Using an immersion blender, carefully puree the soup until it reaches a smooth consistency. This creates a creamy foundation while still allowing for some chunkiness later. Taste the soup and adjust seasoning with more salt and pepper if needed.
Stir in Beans, Corn, and Chicken: Add the black beans, frozen corn, and shredded chicken to the blended soup. Heat gently until everything is warmed through, about 5 minutes.
Prepare Crispy Tortilla Strips: While the soup simmers, heat a small skillet over medium-high heat with a splash of vegetable oil. Fry the tortilla strips in a single layer for 30 to 45 seconds per side, turning once, until golden and crisp. Use tongs to remove them and place on paper towels to drain excess oil.
Serve and Garnish: Ladle the hot soup into bowls and top with shredded cheese, diced avocado, cilantro, sliced green onions, crispy tortilla strips, and jalapeño slices if desired. Serve immediately with lime wedges on the side for squeezing.