Preheat a grill to medium-high heat. Stir together the soy sauce, chili sauce, sesame oil, brown sugar, vinegar, grated ginger and grated garlic in a small bowl. Reserve 2 tablespoons for the vegetables and then stir in the hoisin sauce. Set half aside for serving with the cooked pork chops and stir in 1 to 2 tablespoons water.
Sprinkle the pork chops on both sides with 1/2 teaspoon each salt and pepper for all 4 chops. Place the pork chops and onions on a lightly oiled grill. Grill until the pork chops are just slightly pink near the bone, 6 minutes on the first side and 4 to 5 minutes on the second side. Grill the onions until they are soft. Start brushing both the pork and the onions with the hoisin sauce mixture about halfway through grilling. Transfer the pork chops to a cutting board to rest for about 5 minutes and the onions to a bowl.
Put the bok choy in a large bowl and cover with plastic wrap. Microwave until the center core has softened and can easily be pierced with the tip of a sharp knife, 3 to 5 minutes. Season the bok choy with 1/4 teaspoon each salt and pepper and grill until charred, 2 to 3 minutes per side. Add to the bowl with the onions and gently toss with the reserved 2 tablespoons ginger sauce. Serve the pork chops with the grilled vegetables and the reserved hoisin sauce mixture on the side.