Remove frozen pork chops from wrapper and place in bottom of crockpot. Chop onion and place on top. Mix gravy per instructions on package and pour over pork chops in crockpot.
Set to high temp and cook for 3-4 hours, or about 6 hours on low, timing depends on thickness. Safe internal temp. needs to reach 150 F.
Remove pork chops and whisk in 2 tbsp arrowroot flour or cornstarch to thicken gravy. Serve gravy over pork chops.