In a large pot, cover the diced potatoes with water and bring to a boil. Cook until tender, about 15-20 minutes. Drain and let cool.

In a mixing bowl, whisk together mayonnaise, Dijon mustard, apple cider vinegar, garlic powder, salt, and black pepper until smooth.

In a large bowl, combine the cooled potatoes, dressing, crumbled bacon, cheddar cheese, green onions, and sour cream. Mix gently until well combined.

Cover and refrigerate for at least 1 hour before serving to allow flavors to meld.