Preheat oven to 325°F. Spray a 9×5-inch loaf pan with cooking spray.
Combine flour, sugar, baking soda, and salt in a large bowl. Mix well.
Add chocolate chips and gently mix to combine.
In a medium bowl, mix egg, vanilla, melted butter, apple sauce and zucchini. Add to the flour mixture and stir until just blended.
Pour batter into the prepared 9×5-inch loaf pan.
Bake 45-55 minutes, or until a toothpick inserted in the center comes out clean. Cool for about 10 minutes. Remove loaf from pan and let it cool before slicing.