Lightly spoon flour into dry measuring cups; level with a knife. Combine flour and the next 4 ingredients (through salt), stirring well with a whisk. Add flour mixture to sugar mixture, beating just until moist. Stir in the zucchini and chocolate chips. Spoon batter into a 9 x 5-inch loaf pan coated with cooking spray. Bake at 350° for 1 hour or until a wooden pick inserted in center comes out almost clean. Cool in pan 10 minutes on a wire rack, and remove from pan. Cool completely on wire rack.