Anyone can name themselves anything. Would you say that the Democratic Republic of the Congo is indeed democratic? I am going to guess not.

'Socialism' was rather popular in the early part of the 20th century and National Socialism was a right wing response to that, hence the marketing name.

It was very much corporatist/pro capitalist in its policies and suppressed anything remotely socialist within its borders.

But I suspect you knew that.

It was also attempting a to create a centrally planned economy that would provide for all the populations needs and eliminate the concept of class. Which to me is socialism.