Marinate chops in 1/4 cup of the vinaigrette for 15 to 30 minutes at room temperature.
Remove chops from marinade and gently pat dry. Season with 1/4 teaspoon salt and 1/8 teaspoon black pepper.
Heat 1 tablespoon olive oil in a large nonstick skillet over medium-high heat. Saute pork chops 2 minutes per side. Set aside.
Add 1/2 cup of the chicken broth, grapes and remaining 1/4 cup vinaigrette to skillet. Simmer over medium heat for 5 minutes, stirring occasionally.
Add pork chops back into skillet and cook for an additional 5 minutes or until internal temperature registers 160 degrees F on an instant-read thermometer.
Prepare couscous following package directions, substituting 1-1/4 cups chicken broth for water.
To serve, spoon couscous onto a large serving platter. Place pork chops on top; spoon grapes and sauce over the chops and serve.