The difference between the Nazis and the Soviets is pretty simple. The end result of Nazi debauchery is to kill other people, other races, the "genetic undesirables of society," ideologically. They wanted to kill people.
The end result of Soviet debauchery was essentially the death of human nature as we know it. Here's one example to really prove the point: Consider Orwell's 1984 and how it has been cited as a critique of Stalinism. Remember the "Anti-Sex League"? One might think it was invented as a natural conclusion of demanding absolute loyalty like under Stalin, but taken to even higher extremes, but in fact, it was effectively already thought up under Stalin.
The Soviets attempted to minimize sexual education under Stalin as much as possible and keep society relatively asexual, where the only real intense loyalties was toward the party. This was to such an extent that "sexual crimes" were a thing. Homosexuals got affected by this especially, and in fact, their treatment by the USSR could be considered even worse than how homosexuals treated the Nazis. It was so bad that once the Soviets got into Germany and even other territories, the Soviets had fun raping and killing a lot of people; even Soviets in concentration camps.
In addition, this same ideology centered on the death of human nature as we know it was systematically spread to...Pretty much every other Communist country we know of. Very few countries came to Communism without the USSR propping them up. China is the pivotal example, with Mao and his CCP directly under the tutelage of the USSR's Communist Internationale. Meaning that in large part, the PRC's existence can be in part blamed on the Soviets, a Communist experiment possibly even worse than the USSR's highest debaucheries.
"MiG Pilot" is a pretty good description of life in the USSR. The USSR pretty much wanted humanity to be completely soulless and animal-like, even if they disguised it under some sense of "utopia" or whatever. Even Nazi Germany's worst monsters at least held some semblance of humanity; Josef Mengele, a cruel human being, at least sometimes spared a life or gave lolipop to his victims or people that he occasionally let go, and it's not like he needed to do such things.
I've never heard of such stories from any of the USSR's worst monsters, and that shows the type of society they wanted and the type of society that they largely got.
Germany at least treated "its own" relatively well. As long as you made a hand wave or two with a simple phrase, you were pretty much safe, and besides that, the life of a German who did the bare minimum to not go against the authorities could be considered acceptable by our standards. Not so in the USSR across its entire lifetime.
Even though the Nazi committed brutal genocides, the Aryans in Nazi Germany didn't lived in fear like the people in USSR did. Furthermore, their economy skyrocketed as Hitler introduced revolutionary policy to tackle unemployment. The Russia meanwhile had gulags and it's equivalent to concentration camps and sometimes it's conditions were way horrid than the Jewish camps. The Nazi were legally and willingly elected by the people of Germany while the USSR started a revolution most people would unwilling to accept. Some countries were too scared of USSR atrocities that they hailed Nazis as liberators.
While Nazi Germany committed heinous, horrific acts such as Kristallnacht, The Holocaust, Roma Genocide, and tried to conquer all of Europe and enforce totalitarianism, I simply believe that the USSR was worse. The Famines and Democides committed by the USSR greatly outnumber those of the Nazis, and were being done before and after the end of Nazi Germany (See the Holodomor). The USSR also encouraged communist revolutions in China, North Korea, Vietnam ,Cambodia and Cuba, causing via affiliation the millions of deaths under Mao,Ho Chi Minh, Pol Pot, Castro, Guevara, Xiaoping, Kim Il Sung etc. They also like the Nazi's sought eventual control over Europe, conquering several countries in Eastern Europe and enforcing brutal oppressive regimes up until the 1980s, including Poland, Yugoslavia (to an extent), East Germany, the Baltic States, and Ukraine. The Soviet Gulags were equivalent or in some cases worse than the Nazi Death Camps, and existed for 30 years, longer than Nazi germany existed at all. Also, the USSR Came to power and enforced it through violence and repression, whereas at least in Germany the Nazi's were "democratically" elected and didn't crush opposition in a 4 year civil war. Finally, the Soviet Union in WW2 committed horrific war crimes on par or even worse than those of the Nazis, to the point that some peoples in Finland, Estonia, Latvia etc even saw the germans as "liberators" (thought to be fair they didn't know about the Nazi's plan to remove the Slavic peoples). Overall, the Soviet Union did acts as bad as the Nazi's for a longer time, and impacted the world more, by affecting more people in more countries, and killing far more people than the Nazis did. Both are still horrific though....
Nazi Germany started World War 2 which killed up to 78,000,000 people, 55,000,000 of which were innocent civilians. They also commited the Holocaust which killed up to 11,000,000 people. The Soviet Union killed more but the Nazis planned to kill more as Hitler planned to kill up to 50,000,000 Soviets before it can annexed into the Third Reich. Hitler planned to kill millions of innocents just because of racism and wanting to create an aryan world. Nazism is also much worse of an ideology than communism as it involves extreme brutality against Jews, Slavs, Gypsies, Homosexuals, Romas, and other stuff. The Nazis oppress people that called them liberators and even killed them in concentration camps and shooting massacres. The Soviets killed more people but never matches the Nazis as they killed mainly their own people while Nazis killed millions of "undesirable" races.