Preheat oven to 375 degrees F. In a large bowl combine chicken, spinach, and pizza cheese. Stir in 1/2 cup of the pizza sauce.
On a lightly floured surface, roll one package of the pizza dough to a 12-inch square. Cut into four 6-inch squares.
Place about 2/3 cup of the chicken mixture onto half of each dough square about 1/2 inch from edge. Moisten edges of each dough square with water and fold over, forming a triangle or rectangle. Pinch or press with a fork to seal edges. Using the tip of a knife, cut small slits into tops of triangles or rectangles; place on an ungreased baking sheet.
Repeat Steps 2 and 3 with second package of pizza dough. Brush tops of calzones with milk and, if desired, sprinkle with Parmesan cheese. Bake about 18 minutes or until calzones are golden brown and heated through. In a small saucepan heat the remaining pizza sauce; serve with calzones.