Pat chops dry with paper towel, and season on both sides with salt and pepper.
Heat skillet over medium-high, and add oil to the pan.
Add chops to the hot pan in batches, 2-3 at a time, making sure there is room all around them, and sear on both sides to a crusty golden brown, about 4 minutes on each side, depending on the thickness of the chops. Internal temp should be 150 F. Chops should be very slightly pink inside.
Transfer chops to a serving platter.
Add to skillet, the apple juice, vinegar and brown sugar, whisking to scrape up and incorporate the pan juices.
Continue cooking until sauce is reduced by half, then add the onions, cooking for about 5 minutes until softened and caramelized.
Add the apple slices to the pan and cook and stir until the apples are tender and golden brown. Add more apple juice if sauce is reduced too much. Cook to a fairly thick, shiny glaze.
Pour sauce and apples over chops, and serve.
Notes
White wine, apple cider (soft or hard), or apple cider vinegar can be used instead of apple juice for tasty variations.