Line a 5-1/2- to 6-quart slow cooker with a disposable cooker liner. Lightly coat liner with cooking spray; set aside. Reserve 1 teaspoon of the lemon peel. In a small bowl stir together the remaining lemon peel, the sage, seasoned salt, and pepper. Remove three-quarters of the sage mixture and rub onto chicken legs. Place chicken in slow cooker.
Meanwhile, in a large skillet cook mushrooms and garlic in hot butter over medium heat for 3 to 5 minutes or until just tender. Stir in remaining sage mixture. Transfer mushroom mixture to a large bowl. Add baguette pieces and carrot. Drizzle with broth, tossing gently to combine. Lightly pack stuffing on top of chicken in cooker.
Cover and cook on high-heat setting for 4 to 5 hours. Using a slotted spoon, transfer stuffing and chicken to a serving platter; discard juices in cooker. In a small bowl combine reserved 1 teaspoon lemon peel, the walnuts and parsley. Sprinkle nut mixture over chicken and stuffing before serving. Makes 8 servings