Preheat oven to 375 degrees. Spray a 9 x 5-inch loaf pan with nonstick cooking spray.
In a large bowl, mix together the bananas, egg, oil, sugar, and vanilla.
In a small bowl, mix the flour, baking soda, and baking powder.
Pour the dry ingredients into the banana mixture. Mix well. Gently fold in the yogurt and the chocolate chips. Pour into the prepared pan. Bake for 30 - 40 minutes or until done.