Yes, that is the lady. She was a generous fan, who collected many video clips, a lot of which are reposted on YouTube. She used the nickname "Natkins". As an example of her care for the fans, when she had a meeting with the Chicks, she was invited to have lunch first with their blogger, Junichi, who would answer any questions. Instead of accepting on her own, and getting an "inside exclusive", she asked if she could bring a group of other fans too, which he agreed to.
As expected with fan base rivalry generally, not all Dixie fans like Carrie, seeing her as winning awards they would prefer to go to their favourites, but Nancy was not like that. She had a video of Carrie singing "Sin Wagon" on her site.
As far as I know, her surviving family are her brother and nephew - they are very touched by the tributes and remembrances, so thanks to all who posted or prayed for Nancy.