Preheat oven to 350°. Spray a 9-inch springform pan with non-stick cooking spray with flour.
Prepare Crumb Topping: In a small bowl, combine sugar, flour, and cinnamon. Add butter and mix until mixture is crumbly. Set aside.
In a mixing bowl, whisk together flour, baking powder, soda, salt, cinnamon, and pumpkin pie spice; set aside.
In a large bowl combine sour cream, sugar, melted butter, eggs, and vanilla; beat at medium speed of an electric mixer until well blended. Add flour mixture and mix just until blended. Mix in zucchini and cinnamon chips.
Spread batter evenly into prepared pan. Sprinkle with crumb topping. Bake for 40 minutes or until a toothpick inserted into the center comes out clean.
Cool 10 minutes, then run a knife around the edge and remove ring. Drizzle icing on cake. Cool completely before serving. (Unless you're like us and would rather eat it hot even though the cake doesn't cut as well.)
Icing: Whisk together powdered sugar and milk to create a thin glaze.