Preheat oven to 350 degrees F. Spray a 9×5 inch or 8 ½ x 4 ½ inch metal loaf pan with flour-added baking spray.
Mix the flour, cocoa powder, baking powder, baking soda, salt and salt together in a bowl and set aside.In a large mixing bowl, whisk the apple butter, oil and sugar together until smooth.
Add the eggs one by one, then whisk in the vanilla and the yogurt until smooth.
Whisk in the flour, then stir in the chocolate chips.Scrape batter into the loaf pan and sprinkle nuts across the top.
Bake on center rack for 50 to 60 minutes or until a pick inserted in the center comes out clean.
Let cool in the pan for about an hour, then remove from pan and let cool completely before serving.