Stir together the kosher salt, black pepper, garlic powder, smoked paprika, and dried thyme in a small bowl. Pat the pork chops completely dry, rub with olive oil, then coat generously on both sides with the spice mixture and let sit at room temperature for 10 minutes.
Heat a cast iron skillet over medium-high heat for about 2 minutes. Sear the chops undisturbed for 3 to 4 minutes per side until a deep golden crust forms, then pull them at 145°F (63°C) and transfer to a plate tented loosely with foil.
Lower the heat to medium and add the butter to the same skillet, scraping up the browned bits. Add the peach wedges in a single layer cut side down and cook undisturbed for about 2 minutes until golden, then stir in the garlic and cook 30 seconds until fragrant.
Sprinkle the brown sugar over the peaches and stir gently. Pour in the balsamic vinegar, Worcestershire sauce, red pepper flakes if using, and chicken broth, scraping the pan bottom, then simmer 3 to 4 minutes until slightly thickened. Stir in the fresh thyme and season with salt and pepper.
Return the pork chops and any collected juices to the skillet, spoon the peaches and glaze over each chop, and simmer for 1 to 2 minutes so the flavors meld and the chops warm through.
Remove the skillet from the heat and let the chops rest in the pan for 5 minutes. Spoon extra glaze and peaches over each serving, scatter with fresh thyme, and serve warm straight from the skillet.