Pour oil into a 10- to 12-inch nonstick frying pan over medium-high heat. When hot, add pork chops and cook, turning once, until browned on both sides, about 4 minutes total. Transfer pork chops to a plate.
Reduce heat to medium and add onion. Stir frequently until onion is limp, 5 to 8 minutes. Stir in wine, jam, and mustard, and bring to a simmer.
Return pork chops to pan and cook until they are barely pink in the center (cut to test), about 5 minutes. Sprinkle with salt and pepper. Transfer chops to plates and spoon sauce over them.