Is it a book you bought from the Nook shop with DRM, or a sideloaded book? I have a NookColor, but I'm sure it's the same for NT, there is no way to edit meta data on the Nook itself. I have taken to using the free Calibre software for all my sideloaded books, which does allow for editing meta data. http://calibre-ebook.com/
I want to edit some metadata to one of the ebooks on the Nook Tablet. Where do I find the option to do this?
I would suggest using Calibre. If it doesn't have DRM it's blissfully easy. If the book has DRM, you won't be able to do anything with it, legally. However, there are ways to break the DRM, including plugin's for use with Calibre. It's up to you to decide if breaking DRM is something you want to do.