Both were great successes initially and both were extremely cruel to the Russians.
But that's where the similarity ends.
The Mongols invaded from the East, the Nazis invaded from the West.
The Mongols travelled more 4,600 km, the Nazis travelled 2,200 km.
Initially, the Mongols were fighting against odds of about 4 to 1, the Nazis had the advantage of 1.35 against 1.
The Mongol invasion was a success -- resulting in the Mongol-Tatar Yoke of more than 240 years.
The Nazi invasion, Operation Barbarossa, was a failure.
Author of "Taierzhuang 1938 – Stalingrad 1942" (ISBN 9780983843597)
Excerpts -- http://numistamp.com/Taierzhuang-1938----Stalingra...