Preheat oven to 350F. Grease or spray 10 cups of a standard muffin tin.In a large bowl, stir together the nut butter, syrup, vanilla, and salt until smooth. Stir in the zuchini, cocoa powder, coconut flour and baking soda until well blended. Stir in 4 tablespoons of the chocolate chips.Divide batter evenly between prepared cups, smoothing tops with moist fingertips; sprinkle tops with remaining chocolate chips.Bake in preheated oven for 24 to 28 minutes until set at edge (center may still look moist; do not overbake). Cool completely in tin set on a wire rack.