Heat your Instant Pot on saute mode with 1/2 tbsp avocado oil. Once hot add diced onion and red pepper. Fry until the onion is translucent, then remove all from the pot.
Add 1/2 tbsp oil to the pot. Combine rub ingredients, massage into the chicken breasts. Sear on both sides, then remove and shut the Instant Pot off. Deglaze the pot by pouring 1/2 cup chicken broth in and scraping away the little bits from the bottom with a wooden spoon *see Instant Pot specific tips below.
Add the chicken back into the broth and, without mixing, dump the remaining ingredients on top of the chicken in this order: onion and red pepper, chopped jalapeños *see notes 3&4, diced tomatoes, tomato paste and lastly the remaining bone stock or chicken broth. Again, do not mix.
Secure the lid of the instant pot and turn the valve from venting to the sealed position. Cook on the Pressure Cook setting for 25 minutes, naturally release for 5 minutes, then carefully, quick release.
Once all of the steam has been released, open the lid of the Instant Pot. Remove the chicken and mix the tex mex cheese into the Keto Chicken Taco Soup. Use two forks to shred the chicken into chunks and then place back into the soup. Mix and serve hot with toppings of choice and tortilla strips.