Melt butter in large skillet on medium heat. Add celery; cook and stir 5 min. or until crisp-tender. Stir in water. Bring to boil. Remove from heat. Stir in stuffing mix, cranberries and nuts. Add 1 cup cheese and egg; mix lightly.
Spoon into 8 muffin pan cups sprayed with cooking spray, mounding stuffing mixture as necessary to fill cups. Sprinkle with remaining cheese.
Bake 10 min. or until stuffing cups are heated through and cheese is melted.