Nate Dogg -- Performing at Coachella ... From Beyond the Grave

Nate Dogg -- Performing at Coachella ... From Beyond the Grave: Nate Dogg isn't letting a little thing like death keep him away from Coachella this weekend -- sources tell TMZ, the rapper will be making a very special guest appearance on stage ... in the form of a HOLOGRAM.Sources tell us, Dr. Dre didn't want to…