Turn your Instant Pot on the SAUTE function, and add the oil.
When it reads “hot”, place the chicken breasts in and brown on each side. Cooking for 3-4 minutes a side.
Remove from pot, and add in chicken stock to deglaze the pan. Use a wooden spoon to scrape off any of the brown bites.
Add butter, the chicken breasts, lemon juice, and capers to the pot.
Place lid on the pot and lock into place. Set valve to “sealing”
Set pot to manual high pressure and cook for 4 minutes.
Let pressure naturally release for 5 minutes, then turn valve to “venting” and remove lid.
Take the chicken pieces out of the pot, and turn it onto the SAUTE function. Combine the corn starch with the cold water, and use a fork to whisk it together, then add it to the sauce in the pot.
Cook for 1-2 minutes until thickened, then spoon over the chicken.
Garnish with fresh parsley and serve immediately