Drain (or strain) the sour cream so it is as thick as possible. Place it in the food processor along with the sautéed onions. Puree until totally smooth, then stir in 2 tablespoons of fresh chopped chive. Salt and pepper to taste.
Scoop the sour cream and onion dip filling into a plastic zip bag. Snip off one corner and use the bag to pipe the filling into the centers of each egg white. Garnish with chopped chive or crumbled potato chips, or both. Cover and refrigerate until ready to serve.