Roughly chop the celery, carrots, onion, bell peppers, jalapeño, and cilantro, and set aside in a large bowl.
Add butter and olive oil to a large pot over medium high heat. Once the butter has melted, add garlic and sauté for 2 minutes.
Add in the chopped veggies, and season with garlic powder, chili powder, onion powder, oregano, and salt. Let the veggies cook down for about 10 minutes, stirring often.
Add the chicken stock and 1 chopped tortilla. Cover and bring to a boil. Once bubbling, continue to cook on medium high for about 10 minutes, then drop the heat to low. Add the chilis in adobo.
Using an immersion blender, blend the soup on high until smooth. Once it is fully blended, return the soup to medium high, cover, and cook for about 30 to 40 minutes, stirring occasionally.
Add the remaining 6 chopped tortillas, cooking for about 5 minutes to soften. Use the immersion blender to blend until smooth. Stir in the shreedded chicken and cook covered on low for 30-45 minutes more.
Serve with avocado, cilantro, queso fresco or cotija cheese, and fried tortilla strips.