Preheat your oven to 350°F (175°C).
Grease your loaf pan with butter or cooking spray.
In a large mixing bowl, beat the butter and sugar together until light and fluffy.
Add the eggs, sour cream, mashed bananas, and vanilla extract. Mix until well combined.
In a separate bowl, whisk together the flour and baking soda.
Gradually add the dry mixture to the wet ingredients, stirring gently until just combined.
Fold in the chocolate chips until evenly distributed.
Pour the batter into the prepared loaf pan and smooth the top. Bake for 55-65 minutes, or until a toothpick comes out clean.
Let it cool in the pan for 10 minutes, then transfer to a cooling rack.