Press the SAUTE button. Add olive oil once it heats up.
Add chicken breasts, onion, and then season with salt and pepper as desired.
Cook the chicken for 5-6 minutes, just until all the chicken pieces are seared.
Pour in the chicken stock and deglaze (scrape) the bottom of the pot to make sure there are no burned pieces left on the bottom.
Press CANCEL to turn off the saute function. Layer in the potatoes, carrots, celery, corn, salt, pepper, garlic powder, and poultry seasoning. Do not stir together – leave in these layers.
Press the MANUAL button and set the timer for 4 minutes. Once it is done cooking, let it do a NATURAL RELEASE for 7 minutes.
After the natural release, move the valve from sealing to venting to let the remaining pressure release.
Remove the lid. Press the CANCEL button so that it stops cooking. Stir in the frozen peas. Once the peas have been mixed in, pour in the milk (make sure that you do the peas first because it will cool down the food enough to add the milk without having it curdle).
Press the SAUTE button. Let the mixture start to bubble. In a small bowl, mix together melted butter, garlic, and flour.
Add in butter and flour paste into the pot and mix. Stir occasionally until the mixture reaches the desired consistency (if you want it to be thicker, let it saute for longer). The potatoes will break down as you stir and help to thicken the sauce. Season with more salt and pepper, if desired.
Cook biscuits as directed on package. Scoop chicken pot pie mixture into bowls and top with a warm biscuit.