Step 1: Using a sharp knife, on a cutting board, remove the corn kernels from the uncooked ears of corn. (If using frozen, canned, or creamed corn, see the notes section below.)
Step 2: In a large pot on medium-high heat, warm the olive oil and butter. Add diced onion and green bell pepper and cook for 3-4 minutes until tender. Add minced garlic and cook for an additional minute.
Step 3: Add diced tomatoes, corn kernels, chili powder, cumin, and salt, and cook for another 1 minute until fragrant.
Step 4: Pour in broth and give it a good stir to ensure everything is well combined. Then add chicken breasts into the pot, ensuring they are submerged in the broth, reduce heat to a simmer, and cook for 20 minutes. (If using leftover chicken see the notes section below.)
Step 5: After 20 minutes, remove the chicken breasts from the pot and place them on a cutting board. Using two forks, shred the chicken into fine strips or bite-size pieces, and set it aside.
Step 6: Using a measuring cup, remove 3 cups of the soup from the pot, add it to a blender, blend until smooth, and then return it to the pot. (If you have an immersion blender, you can do this directly in the pot, but only partially blend the soup.)
Step 7: Return the shredded chicken to the pot, pour in heavy cream, stir to combine, and allow to simmer for an additional 5 minutes. As it does, taste and adjust salt and pepper as needed.
Step 8: To serve, ladle the soup into bowls and serve with a sprinkle of cotija cheese, cilantro, and/or red pepper flakes on top.
Step 9: Any leftover soup can be stored in an airtight container in the fridge for up to 5 days or in the freezer for up to 3 months.