Cook elbow macaroni according to package instructions until al dente. Drain and rinse with cold water. Allow to cool completely.
In a large bowl, combine mayonnaise, sour cream, Dijon mustard, white vinegar, sweet pickle relish, salt, pepper, paprika, and garlic powder. Mix well.
Add cooked and cooled macaroni to the bowl with the dressing. Stir to coat evenly.
Gently fold in chopped hard-boiled eggs, celery, and red onion until well combined.
Cover and refrigerate for at least 1 hour to allow flavors to meld.
Before serving, garnish with chopped fresh chives.
