Set pot to saute and add olive oil. Add chicken pieces in when hot and brown on sides until there is no pink on outsides.
Add chicken broth and use wooden spatula to scrape stuck on pieces of food off bottom to deglaze pot.
Turn pot off now. In a bowl whisk together all other ingredients EXCEPT for the peanut butter and cornstarch. Pour this into the pot.
Use a spoon to drop dollops of peanut butter into the pot but DO NOT stir.
Close lid and steam valve and set to high pressure for 8 minutes followed by a 5 minute natural release. Then release rest of pressure.
Lift lid and if you want sauce thicker whisk together cornstarch with a few tbsp of cold water until smooth. Set pot to saute and when sauce bubbles add cornstarch slurry. Stir and allow to thicken, then turn pot off and serve.