Nismo MFD from Nengun or Greenline are just upgraded replacement boards for the standard MFD, you will still need a complete MFD to start with.
The MFDs work just like any boost/oil temp/water temp type gauge ,they just need wiring up.
They do not need a 34R harness, although this makes very much easier (plug and play)
You will just need to go thru and hook up all needed sensors, wiring diagram info is in previous post links.