>>54746408National socialism is hypocritical. It subjugates local nationalism in pursuit of the state's idea of nationalism. For example, consider the plight of a Venitian nationalist living within an Italian nationalist government, forced to support non-Venetians with his tax dollars. Or the European nationalist living within a German nationalist government, prevented from bringing Europe together through trade and camaraderie. A nation is a culturally similar group of people, defined organically, and not simply everyone living in a state's jurisdiction.
And even if the government you're living under subscribes to your particular brand of nationalism, there is no guarantee it will remain so. When the government controls all property (chiefly, infrastructure), they can just as easily force immigration as they can prevent it. Hitler one decade and Merkel the next, and if you, as a nationalist, are outnumbered in your country then you're fucked (particularly true of a democracy). A society of private property owners with like minds is far more enduring.
The point being, nationalists must support private property or they're defeating their own point.