In a bowl, stir to combine pineapples with juice, vinegar, mustard, soy sauce and ginger. Set aside.
Set your pressure cooker to brown (according to your manufacturer's instruction booklet). Heat the 1 tablespoon of oil. Add pork chops and brown on both side. Remove chops from cooker and set aside.
Add onions to the pressure cooker and saute for about 2 minutes. Place pork chops back in the cooker. Pour sweet and sour sauce over chops.
Secure your pressure cooker and cook on high for 10 minutes (according to your manufacturer's instructions).
When your pressure cooker is done cooking, carefully release steam and remove lid according to instruction booklet for your pressure cooker.
Transfer chops to serving platter.
Set your pressure cooker to brown and add and dissolve cornstarch to remaining liquid in cooker. Cook, stirring frequently until sauce thickens, about 1 to 2 minutes. Pour sauce over chops and garnish with chopped parsley or cilantro. These pressure cooker pork chops are super served over rice.