They are actually powered by Nissan, no official Nissan entries. All of the entrants are LMP2's which us prototype chassis not resembling official road going cars. I thought the Peter Dumbreck was going to have the Sumo Powered GT-R at LeMans, but I did not see it on the entry list.
Check this Nissan car car on display:
YouTube - NEW NISSAN LEAF NISMO RC - Test Session
It will be on track for a special promo Saturday. Painted white and blue now...but I like the all Carbon Fiber look personally.