Boil the cubed potatoes in salted water for about 15 minutes until fork-tender. Drain and let them cool slightly.
In a large bowl, mix sour cream, mayonnaise, Dijon mustard, garlic powder, salt, and black pepper until smooth.
Add the cooked potatoes to the dressing and gently toss to coat. For a heartier meal, pair this salad with Baked Cream Cheese Chicken.
Fold in the shredded cheddar cheese, crumbled bacon, and sliced green onions. Stir until evenly combined.
Refrigerate for at least 30 minutes before serving for the best flavor. Enjoy chilled!