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