Place the halved or quartered baby potatoes in a large pot and fill it with cold water until the potatoes are covered by about an inch. Add a pinch of salt.
Bring the water to a boil over medium-high heat. Once boiling, reduce the heat to medium and let the potatoes simmer for about 15-20 minutes, or until fork-tender.
Drain the cooked potatoes in a colander and let them cool for a few minutes.
In a large mixing bowl, combine the sour cream, mayonnaise, lemon juice, Dijon mustard, garlic powder, onion powder, salt, and black pepper. Whisk until smooth.
Add the cooled potatoes to the mixing bowl and gently fold them into the dressing using a wooden spoon or spatula.
Stir in the chopped dill and green onions until evenly distributed.
Taste and adjust seasoning with additional salt and pepper if needed.
Cover the salad and refrigerate for at least 30 minutes before serving to let the flavors meld.