Bring a large pot of salted water to a boil. Add potatoes; cook until tender but still firm (about 15 minutes).
Drain and set aside to cool.
In a large bowl, combine potatoes and chopped eggs.
Mix yogurt, mayonnaise, green onions, mustard, dill weed, and garlic powder.
Pour dressing over potatoes and eggs; toss and chill until ready to serve.