Heat oven to 350°F. Line a 12-cup muffin pan with liners.
Mash bananas in a bowl until mostly smooth with a few small bits.
Whisk flour, baking powder, baking soda, salt, and cinnamon in a large bowl.
Whisk sugars, oil, sour cream, beaten eggs, vanilla, and mashed banana in another bowl.
Fold dry ingredients into wet until just combined; stop when no dry streaks remain.
Stir in chocolate chips, reserving a spoonful for garnish.
Divide batter evenly among liners, filling each about three-quarters full.
Bake 17–20 minutes until tops spring back and a tester comes out clean.
Cool 10 minutes in pan, then transfer cupcakes to a rack to cool completely.
Beat cream cheese and butter until creamy and fluffy, about 2 minutes.
Add powdered sugar, vanilla, and salt. Mix on low, then beat until smooth.
Beat in cream a little at a time until spreadable. Frost cupcakes and top with chips.