Nazism was the political and economic system of Germany since 1933 through 1945. There were no options. If anyone managed to do well, they did so as a Nazi. They couldn't be anything else. It is also inevitable that the largest industrial firms would have been contractors to the war effort. You don't produce fighters and bombers from Grandma Olga's sewing shop.

Now, firms that became wealthy from slave labor, that would be to condemn.