According to this site, among other sites, it appears that Korn will not be covering that one NIN song after all, but instead will be ruining "Fight The Power" by Public Enemy:
Korn look to have abandoned their plans to cover and have instead opted to cover Public Enemy's "Fight The Power", complete with a guest appearance from rapper Lil Jon. The bands version of "Fight The Power", along with their cover of Pink Floyd's "Another Brick In The Wall", are both expected to show up on the groups forthcoming 'best of' album, which is planned for a release this fall. One of the aforementioned tracks is also expected to be used as a single from the release with a video to be shot for it in the coming weeks.
Thanks to everybody who passed along this nugget of info. Oh, and the Meathead Perspective has kindasorts been updated.