Season the pork chops with salt and pepper on both sides.
Heat the olive oil in a large skillet over medium-high heat. Brown the pork chops on both sides, about 2-3 minutes per side.
Transfer the pork chops to your slow cooker.
In the same skillet, add the chopped onion, minced garlic, and sliced mushrooms. Sauté for about 5 minutes, until the vegetables are soft and lightly browned.
Pour the mushroom mixture over the pork chops in the slow cooker, covering the pork chops completely.
In a medium bowl, whisk together the condensed cream of mushroom soup and chicken broth until smooth. Pour the mixture over the pork chops and mushrooms in the slow cooker.
Cover the slow cooker and cook on low for 6-8 hours, or on high for 3-4 hours, until the pork chops are cooked through and tender.
In the last 30 minutes of cooking, stir in the sour cream and mix well. This will create a creamy mushroom gravy.
Remove the pork chops from the slow cooker and transfer them to a serving dish.
Garnish with chopped fresh parsley, if desired, and serve hot.