Slice the yellow onion and finely chop garlic cloves and jalapeño before adding to a large pot with olive oil. Sauté until onions, garlic, and jalapeño over medium heat until garlic and onions are fragrant, around 2 minutes.
If using chicken breast, slice into strips and season with salt and pepper before adding to the pot with onion and garlic.
Sprinkle in taco seasoning (or chili seasoning blend) and a pinch of black pepper and continue cooking until chicken has cooked through. Remove chicken from heat and set aside on a cutting board to cool.
Meanwhile, reduce the heat of the pot to medium low and add in the can of diced tomatoes, cumin, and chicken bone broth and stir to combine.
If you are using chicken drumsticks, add to the pot at this step. Then, cover pot with a lid and let simmer for 10-15 minutes (you may need to reduce the heat to low if the soup begins to boil vigorously).
If using chicken breast, shred the cooked chicken while the soup is simmering. To do so, take a fork in each hand and, starting towards the middle of the chicken strip, begin pulling in outward motions using the forks until shreds form. For a quicker method (and thinner shreds), toss the chicken in a high-speed blender or food processor and pulse 3-5 times until chicken is shredded.
After the soup has simmered, set the heat to low if you haven't already, and, if using chicken drumsticks, check to ensure they are fully cooked. If they have not cooked fully, continue simmering the soup with the lid on the pot until cooked through. Then, remove from heat and let cool on a cutting board.
Taste soup broth and adjust seasoning as desired, adding more salt or chili seasoning to your taste preference. If using chicken breast, add shredded pieces to the pot. Then, add corn and black beans.
If using chicken drumsticks, remove meat from the bones, and toss the bones. Then, shred the meat using the same steps above (either with two forks, or in a high-speed blender or food processor). Add to soup.
Stir all ingredients to combine. Then, serve in a bowl and top with tortilla strips, shredded cheese, avocado, sour cream, and cilantro.