The Molotov-Ribbentrop Pact says otherwise.

German and Soviet troops that met in Poland after invading from the west and east had no trouble in celebrating their victory together, holding parades and such.

As John Gunther—who was in Moscow when the world learned of the pact's existence in August 1939—wrote, "communism and Fascism were more closely allied than was normally understood".

What about horseshoe theory?

Nazism is far-right and authoritarian. Socialism is just far-left, but not necessarily authoritarian. Soviet-style socialism was very authoritarian and that's why it got its bad reputation. And you can be authoritarian and not even be on the left-right axis - Saudi Arabia is an example, as is Afghanistan now.

Both of those countries are theocratic and extremely socially conservative, which places them on the far right.

Maybe, but they don't have really free markets either. In this regard, North Korea is more of an absolutist monarchy than any previously known form of socialism.