1Heat oven to 350°F. Grease 12-cup fluted tube cake pan with shortening; lightly flour. In medium bowl, mix flour, pumpkin pie spice, baking powder, baking soda and salt; set aside.
2In large bowl, beat butter, brown sugar and granulated sugar with electric mixer on medium speed until creamy. Add eggs, one at a time, beating on low speed after each addition until blended. Add pumpkin and 2 teaspoons vanilla; beat on medium speed until blended. On low speed, beat in flour mixture alternately with 1/2 cup milk until smooth. Stir in 1 cup of the chocolate chips. Spoon batter into pan.
3Bake 55 to 60 minutes or until toothpick inserted in center comes out clean. Cool 10 minutes; remove from pan to cooling rack. Cool completely, about 1 hour. In medium bowl, mix all glaze ingredients until smooth and thick. Drizzle glaze over cake. Sprinkle with remaining 1/4 cup chocolate chips.