In a large saucepan of salted water, boil potatoes for roughly 10 minutes or until just cooked.
Drain and refrigerate for 1 hour, or in the freezer for 10 minutes.
Once potatoes are cooled, place in a serving bowl and scatter over three-quarters of the spring onions.
In a separate bowl, combine the sour cream and sweet chilli sauce.
Pour over the potato and gently toss to coat.
Serve garnished with remaining spring onions.