Turn on Instant Pot and select Saute, adjust the temperature to High. Once it reads hot, add olive oil and onion, cook stirring for 3 minutes, just until softened.
Add minced garlic and cook for another minute, just until fragrant.
Turn off Saute mode.
Add the chicken breasts (or shredded rotisserie chicken meat) and the rest of the ingredients from the "Pressure Cook" list, placing the cream cheese on top.
Close with the lid, lock it and point the valve to seal. Select Pressure Cook and input 20 minutes.
Once the time has passed, do a 10-minute Natural Pressure Release, after which release manually the remaining pressure.
Open the IP, stir and select Saute, on Medium heat.
If you used chicken breasts, remove them, place on a cutting board, shred and return to the soup.
In a small cup mix cream and cornstarch until combined and add the mixture to the pot. Also, stir in sour cream until melted and fully combined. Adjust for salt and pepper.
Turn of the IP and stir in shredded cheese.
Optional: using an immersion blender, puree a portion of the chili, about 1/2, to thicken it even more.
Serve with your favorite toppings.