Heat oven to 375°F. Spray 9-inch glass pie plate with cooking spray. In 2-quart saucepan, gently mix chicken, celery, onion, mayonnaise, sour cream, soup and water chestnuts. Cook over medium heat until bubbly. Pour into pie plate.
Separate dough into 8 triangles. Arrange triangles, points toward center, over hot mixture. Cut off excess dough in center of pie; do not overlap dough.
In small bowl, mix cheese, almonds and melted butter. Spread evenly over dough.
Bake 35 to 40 minutes or until crust is golden brown.