What else are we supposed to call them, pray tell?
Israeli Nationalists more or less means the same but has less baggage
Zionism existed well before the State and Israel and "Israelis" existed.
I’m aware but I don’t see how that’s relevant. The State of Israel definitively does exist and there are nationalists there who want to expand their borders.
You said "Israeli nationalist" was a suitable alternative term but it's really not, and my point about Israelis demonstrates that. At best, it's only suitable in a post-1947 context, not even half of Zionist history. And there are many different types of Zionism. Are the Labor Zionists of the kibbutzim "Israeli Nationalists"? Maybe in some cases, but it hardly seems the appropriate term to use as a catch-all. Especially since Zionists also largely describe themselves as such. There's nothing wrong with calling a spade a spade.