Zionism does not address Arabs at all. It ignores them, and their needs.
Zionism is more like the American "manifest destiny" doctrine. The purpose isn't to eradicate the Arabs, or even move them out of the way, the purpose is to settle the territory of Israel.
Nazism saw Jews themselves as a problem. Whilst there was some attempt to simply displace them, it wasn't because they were in the way, and preventing German expansion. The Jews themselves were percieved as the problem.
If there were 10 million Jews and 1 million Palestinians, Israel would have given them citizenship long ago, and the place would be peaceful now.
For Zionism, the goal is to get the land. The problem is the Palestinians are in the way.
For Nazism, the goal was to get rid of the Jews. The problem was how best to do it.
That's a fundamental difference.