You're half-right: this battle was used as nationalist propaganda. However, while I'm sure the Nazis took it to new extremes, that usage predates them by almost a century.

Remember that the nation state an accidental invention of the industrial revolution after all; pro-nation state propaganda was happening all over Europe at the time, and a lot of it is quite offensive to our modern eyes.

I find it kind of frustrating that Nazis are mainly depicted as this evil that came into existence in a vacuum, or in the best case solely as a reaction to the situation in Germany after WWI. The seeds of fascism and xenophobia had been shown all over Europe long before that. I suspect Germany just got there first.