Grease and flour two loaf pans
Preheat oven to 325 degrees.
Make Cream Cheese Filling: Beat cream cheese in a small bowl until smooth and creamy. Beat in sugar, orange zest and flour until smooth. Add egg and beat until thoroughly mixed. Set aside.
Make chocolate batter: Whisk together dry ingredients in a medium bowl. In a large mixing bowl, beat oil, sugars, eggs and vanilla until creamy. Stir in sour cream, zucchini and orange zest. Add dry ingredients and mini chocolate chips. Stir just til moistened, being careful not to over beat.
Spread 1/4 of the batter in the bottom of each prepared pan.
Add 1/2 of the cream cheese mixture on top of chocolate batter in each pan.
Divide remaining chocolate batter pour over the cream cheese mixture in each pan. The cream cheese mixture should be mostly covered with the top layer of chocolate batter.
Bake the loaves at 325 degrees for 60-80 minutes. Check after 60 minutes because oven temperatures and loaf pan sizes and materials can vary.
When the bread is done, a toothpick or cake tester inserted into the center of the loaf, in the chocolate will come out clean. Cool in the pans for about 10 minutes before removing to cooling racks to finish cooling.