Propaganda has been around for ages. Otherwise, if by Nazis you mean Germany during WW2 (most people actually do, this is a common mistake as there is a difference) they were way ahead of the curve in terms of jet propulsion, producing the first real jet fighter in the form of the Me.262. Also developed the first true assault rifle, the StG.44 chambered for the 8mm Kurz cartridge which itself was a unique item as the first intermediate cartridge, prior to that it tended to be either submachineguns chambered for handgun cartridges such as the .45 or 9mm (really only effective out to around 100 yards) and rifle chambered for full powered cartridges such as 7.62x54R, 8mm Mauser, and .30-06 (effective out to 800+ yards but heavy and uncontrollable if full automatic), no intermediate and attempts at creating controllable individual portable full auto rifles in such potent cartridges were failures as practical weapons (FG42 or full auto SVT-40 variants for example). Assault rifles are defined by chambering such intermediate cartridgess that may not be effective out as far as a high powered rifle cartridge but are effective out to 300 yards which tends to be the maximum range at which battle occurs most of the time (typically 100 yards and closer). Russia claims they developed their own intermediate round, the 7.62x39, before the Germans, this may or may not be true but in either event it was the Germans that first pioneered the concept and brought it to production.