Prep the oven and the loaf pan. Preheat the oven to 350°F. Grease a standard 9x5-inch loaf pan with butter or non-stick cooking spray; or line it with parchment paper, leaving some overhang for easy removal.
Mash the bananas. In a large mixing bowl, mash the ripe bananas until smooth using a fork or potato masher.
Combine the wet ingredients. To the mashed bananas, add the light brown sugar, granulated sugar, and eggs. Whisk until fully combined. Gradually stir in the melted butter, vanilla extract, and sour cream until the mixture is smooth.
Mix the dry ingredients. In a separate bowl, whisk together the all-purpose flour, baking powder, and a pinch of Kosher salt.
Combine wet and dry ingredients. Gradually fold the dry ingredients into the wet ingredients using a spatula or wooden spoon, mixing just until no streaks of flour remain. Be careful not to overmix to keep the bread tender.
Add the chocolate chips. Gently fold in 1 cup of semi-sweet chocolate chips, distributing them evenly throughout the batter.
Transfer to the pan. Pour the batter into the prepared loaf pan, smoothing the top with a spatula. Sprinkle the remaining ½ cup of chocolate chips evenly over the top for a decorative and indulgent finish.
Bake. Place the loaf pan in the preheated oven and bake for 60–70 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. If the top browns too quickly, tent it loosely with aluminum foil during the last 15 to 20 minutes of baking.
Cool and serve. Remove the bread from the oven and let it cool in the pan for 10-15 minutes. Carefully transfer it to a wire rack to cool completely before slicing. Enjoy!