Mince enough of the red onion slices to have 1/3 cup minced onion.
Put remaining onion slices in a bowl and pour vinegar over them; marinate for 10 minutes. Drain and discard the vinegar.
Heat olive oil in a skillet over medium-high heat. Season pork chops with salt and pepper; fry in the hot oil until nicely browned and no longer pink in the center, about 4 minutes per side. An instant-read thermometer inserted into the center should read 145 degrees F (63 degrees C).
Arrange pork chops onto serving plates; top each with a portion of the red onion slices.
Whisk minced onion, sour cream, Dijon mustard, and apricot preserves together in a bowl; serve with the pork chops.