It is, indeed. We waited on the front porch that Christmas Eve until they opened the doors for the candlelight tour, and there was a hard north wind cutting through our clothing. But, it was worth the wait. The Christmas tree in the big room has to be seen to be believed. It is HUGE! But, not just the tree, every room in that gigantic mansion is fully decorated.
For a virtual tour see this:
https://www.biltmore.com/things-to-do/events/christmas/
Best, SRH