Preheat oven to 425 degrees F (220 degrees C). Grease a large baking sheet.
Whisk baking mix, lemon-lime soda, sour cream, and melted butter in a bowl until batter is smooth. Drop biscuits by large spoonful onto the prepared baking sheet.
Bake in the preheated oven until biscuits are golden brown, 12 to 15 minutes. Let biscuits rest for about 5 minutes before serving.
