Preheat oven to 350. Grease and flour a bundt pan. In a medium bowl, stir together mashed bananas, sugars, butter, milk, and egg. In another medium bowl, whisk together the flour, espresso powder, baking soda, and salt. Make a well in the middle of the dry ingredients. Pour the wet ingredients into the well and stir until just combined. Fold in the chocolate chips. Pour batter into prepared pan. Bake in the center of the oven for about 50-60 minutes, until a toothpick inserted in the center comes out clean. Let cool in the pan for 15 minutes. Turn out onto a cooling rack with parchment paper below and let sit for about 30 more minutes. When cake is barely warm to the touch, make the glaze by mixing the powdered sugar and coffee together with a whisk. You want it to be pourable, but still quite thick. Pour it over the cake, letting it run down the sides, into the middle, and onto the parchment paper below. Let harden--about 15 minutes.