Preheat oven to 350°.
Combine first 5 ingredients in a large bowl, stirring well with a whisk. Lightly spoon flour into dry measuring cups; level with a knife. Combine flour, cinnamon, salt, and baking soda in a medium bowl, stirring well with a whisk. Add flour mixture to pumpkin mixture, stirring just until moist. Stir in chocolate chips.
Spoon batter into 2 (8 x 4-inch) loaf pans coated with cooking spray. Bake at 350° for 1 hour and 15 minutes or until a wooden pick inserted in the center comes out clean. Cool 10 minutes in pans on a wire rack, and remove from pans. Cool completely on wire rack.