Preheat your oven to 350°F (175°C). Grease a loaf pan and set aside.
In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt.
In another bowl, whisk together the buttermilk, vegetable oil, eggs, and vanilla extract.
Pour the wet ingredients into the dry ingredients and stir until just combined. Fold in the chocolate chips.
In a small bowl, mix together the cinnamon swirl ingredients: sugar and ground cinnamon.
Pour half of the batter into the prepared loaf pan. Sprinkle half of the cinnamon sugar mixture over the batter. Pour the remaining batter on top, then sprinkle the rest of the cinnamon sugar mixture on top.
Use a knife to gently swirl the cinnamon sugar into the batter.
Bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean.
Let the bread cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.