Combine the softened cream cheese with milk in a microwave-safe container. Microwave it for 30 seconds, then whisk if possible. Repeat a few times, until the mixture is smooth.
Add the sour cream, onion powder, garlic powder, parsley, and chives and blend well.
Finally, add the cheeses and mix until it's well distributed.
Refrigerate for 2-3 hours or until chilled.