In a bowl or plate combine flour, 1/4 tsp salt and 1/4 tsp pepper. Mix together. Coat each chicken cutlet with flour mixture and set aside.
Once all pieces are coated set pressure cooker to saute and add olive oil. Add cutlets so they're not overlapping so you can lightly brown both sides of each piece. Remove when done and set aside. Once they're all done use 1/4 c the broth to deglaze the pot to get all stuck on pieces off.
Add butter, allow to melt and then add onions. Saute until they're soft, then add mushrooms and remaining salt and pepper, and garlic. Continue to saute for a few minutes just to soften mushrooms.
Add wine and stir cooking for 3 more minutes. Turn off saute function and pour in your broth. Stir contents.
Add browned chicken into the pot now. Close lid and steam valve and cook on high pressure for 8 minutes. Do a quick release.
Remove chicken and keep warm. Set pot to saute again and in a small bowl whisk together 2 tbsp of cornstarch with some of the hot liquid from the pot until it is smooth. Then pour this into your pot once contents are boiling.
Stir, allow to bubble and thicken sauce.
Serve chicken with this mushroom gravy poured on top.