Your owners manual specifies Nissan Matic D. It also states that Dexron III/Mercon may also be used. I would not use any of the higher numbered Dexron or Mercon fluids, e.g. Mercon V, Dexron VI, without Nissan recommendation. While automatic transmission fluids may be identified as interchangable by their manufacturers they may differ in properties (lubricity, detergency) that cause a vehicle manufacturer to specify a certain type or brand.
Steve