For dressing, in a small bowl combine pear nectar, vinegar, and snipped thyme. Whisk in oil. Season to taste with salt and pepper. Set aside.
Place pears on the rack of the grill directly over medium heat. Grill about 8 minutes or just until pears are tender, turning once halfway through grilling. Cool slightly. Cut into thin slices.
Divide greens among 6 salad plates. Arrange pear slices on top of greens. Sprinkle with pecans and cheese. Stir dressing and spoon over salads. Garnish with thyme sprigs. Serve immediately. Makes 6 servings.