Heat olive oil in a large skillet over medium-low heat.
Add the diced onions and salt to the skillet; cook while stirring occasionally until onions are deeply caramelized and golden brown, approximately 25 to 30 minutes.
Remove the skillet from heat and allow the onions to cool completely to room temperature.
In a medium mixing bowl, whisk together the Greek yogurt, garlic powder, onion powder, black pepper, and Worcestershire sauce until smooth.
Fold the cooled caramelized onions into the yogurt mixture.
Gently stir in the minced chives.
Transfer to a serving bowl and refrigerate for at least 30 minutes prior to serving to allow the flavors to integrate.