If today's white supremacists found power, they'd look exactly like Nazis. The enemy might be different, but the mindset of fighting that enemy would be exactly the same, and the white supremacist suddenly finding power would find no other example to take heed of than the Nazis, so we can pretty much almost assume that that's what would happen.
Sure, but it's important to realize that this is true about any supremacist ideology. There's nothing exclusive about either Nazism or white supremacism. ISIL's Islamofascism is the same old crap for example, and it too has a line of historical descent from, e.g. early-20th-c. anti-Semitism. The Grand Mufti of Jerusalem was a raging anti-Semite who met Adolf Hitler and ardently supported his most heinous atrocities.