Place all the ingredients except oil, chicken, chicken stock and hominy in the blender. Blend until pureed. Pour into the pot of an electric pressure cooker or slow cooker, and drizzle with 2 tablespoons of olive oil.
(Optional) Set the lid loosely on top of the electric pressure cooker. Select the saute setting, and saute the tomatillo-chile mixture to develop a roasted flavor. Turn off the heat after 20 minutes, and wait a few minutes for the bubbling to stop. Remove the lid.
Add the chicken stock and chopped chicken, and stir to combine. Seal the pressure cooker and cook using the soup setting, or cook on high pressure for 15 minutes. Allow pressure to come down using a natural pressure release. If using a slow cooker, cook on high for 4 hours.
Once the pressure is released, add the drained hominy. Simmer the soup for about 10 minutes to heat through. Serve with desired toppings.