1. Place stock, chicken, split onion, empty corn cobs, scraped corn milk, 2 whole garlic cloves, and chiles in a large saucepan. Bring to a boil over high heat, then reduce to a simmer. Cook for 30 minutes, turning chicken occasionally and topping up with water as needed. Discard onion, corn cobs, and garlic. Transfer chicken to a plate, cool slightly, and shred into strips.

2. Adjust oven rack to 4 inches below broiler and preheat broiler to high. Place tomatoes cut side-up on a foil-lined pan and broil until charred and softened, about 15 minutes.

3. Combine roasted tomatoes, stock, and softened chiles in a blender. Blend on high until smooth and set aside.

4. Heat oil in a large saucepan over medium-high heat until shimmering. Add diced onions, poblano, and corn kernels. Season with salt and pepper and cook until onions are softened, about 5 minutes.

5. Add minced garlic and cook for 30 seconds until fragrant. Add cumin and oregano, stirring frequently for another 30 seconds.

6. Stir in beans and half of the cilantro. Strain blended tomato-chile stock into the pot and stir to combine.

7. Whisk corn flour into soup. Bring to a simmer and season with salt and pepper. Cook 5 to 10 minutes, stirring frequently, until onions and poblano are softened.

8. Serve hot, garnished with shredded chicken, avocado, fried tortilla strips, scallions, lime wedges, and remaining cilantro.