Preheat the oven to 350 degrees F (175 degrees C). Grease two 9x5-inch loaf pans.
Sift flour, baking soda, salt, nutmeg, cinnamon, and baking powder together in a bowl.
Beat eggs in a mixing bowl with an electric mixer until light and fluffy. Add sugar and beat until well blended. Stir in zucchini, oil, walnuts, chocolate chips, orange zest, and vanilla. Blend in flour mixture. Divide batter evenly between the prepared loaf pans.
Bake in the preheated oven until a toothpick inserted in the center comes out clean, about 50 minutes. Let cool slightly before removing loaves from the pans. Chill loaves in the refrigerator before slicing.