Add the liner to your Instant Pot and press the Saute button. When the screen reads 'HOT', add both the oil and onions into the pot. Saute, stirring often, until the onions are soft then pour in the broth.
1 tbsp canola oil, 1 large yellow onion, 8 cups chicken broth
Add the celery, carrots, tomatoes, chiles, three tablespoons of taco seasoning, garlic powder, paprika, chicken, and tortillas to the pot.
3 stalks celery, 2 large carrots, 1 14 oz can fire roasted diced tomatoes, 1 7 oz can diced green chiles, 3 1/2 tbsp taco seasoning, 1 heaping tsp garlic powder, 1/8 tsp smoked paprika, 2 lbs boneless, skinless chicken breasts, 15 6 inch corn tortillas
Add the lid to the pot, turning to close, and make sure the vent valve is in the sealed position. Press the 'Pressure Cook' (normal) button, and cook for 10 minutes.
When the cook time's done, allow the pot to sit and naturally release for 10 full minutes. Carefully turn the vent valve to release any remaining trapped steam, then open the pot and set the lid aside.
Using tongs, transfer the chicken breasts to a cutting board and shred or chop it up. Be careful since it will be hot, then transfer the chicken back into the pot.
Add the sour cream to a small mixing bowl, then add one ladle of hot broth. Quickly whisk together. Pour this mixture into the soup, and quickly stir until evenly incorporated.
1 cup sour cream
Add the shredded cheese to the pot, stirring until completely melted and incorporated.
1 1/2 cups shredded Mexican blend cheese
Carefully taste test the hot soup, and stir in the remaining half tablespoon of taco seasoning if desired. Salt & pepper, to taste.
salt & pepper
Serve warm with your favorite garnishes.