Agree with Coastaljames, it's never that simple. Nazis banned socialists who didn't stand with them, because they banned anybody who didn't stand strictly with the party's line ; and they hated social-democracy, first because they hated democracy, but their economic policy was more radical than theirs, and their social policy not very different. They were certainely rigourous state interventionists at every level. Although big companies were not nationalized and had their management maintained, they were completely under the command of the Nazi government and had to follow strictly its orders and directives, they were left with no freedom, no room for manoeuvre, no policy, strategy or initiative of their own, their executives being de facto reduced to a status of civil servants. This policy was not motivated solely by the need to develop a war machine, but it was at the core of the totalitarian Nazi ideology of complete state control over society. If workers had no freedom of union, it was because no body of citizens was allowed to contest the government's policy, a situation similar to the one met in Communist countries, that everybody agrees enforced an extremist form of socialism. But Nazi Germany was a welfare state, and the workers' social rights were protected.
One could ask why Hitler did not enforce strictly his ideology by proceeding directly to nationalisations, I believe that the answer is easy : he was not strong enough, even at the eve of the war ; had he done that between 1933 and 1939, he would've been deposed. He's been often ascribed the intent to nationalize big business after the war, and is said to have regretted not to have taken the plunge before. In any case, plenty of state-owned companies had already been created during the war, notably under the control of the SS. Nazis were definitely far on the state control and welfare wings of the economical spectrum, and this is what is often considered as meaning socialism.