Preheat the oven to 350°F (175°C). Grease a 9x5-inch loaf pan.
In a large bowl, combine the mashed bananas, granulated sugar, brown sugar, and melted butter. Mix until well combined.
Add the eggs and vanilla extract to the banana mixture, stirring until fully incorporated.
In a separate bowl, whisk together the baking soda, salt, flour, and ground cinnamon. Gradually add the dry ingredients to the banana mixture, stirring until just combined. If using, fold in the chopped nuts and chocolate chips.
In a small bowl, mix together the brown sugar, cinnamon, and softened butter for the swirl.
Pour half of the banana bread batter into the prepared loaf pan. Spread half of the cinnamon swirl mixture over the batter. Pour the remaining batter on top, followed by the rest of the cinnamon swirl. Use a knife to gently swirl the cinnamon mixture into the batter.
Bake for 55-65 minutes, or until a toothpick inserted into the center comes out clean.
Allow the bread to cool in the pan for 10 minutes before transferring to a wire rack to cool completely.