Palestinians are the indigenous people to the land who were ethnically cleansed via Nakba. It's not "nationalism" to allow people to return to the land that was stolen from them.
That is called birthright and the way I see it, it applies to both groups. And the conflict will never be solved (without large scale genocide), if both groups largely negate the other groups rights.
But let's be clear on this: Jews that are not currently in Israel have no right to immigrate there. Jews that are in Israel have no right on any part of the land that isn't already part of Israel proper; and finally, Jews (exactly as much as Palestinians do) have a right to life, property and safety but not necessarily to their own political entity.
To me it seems close to the arguments of the jewish who see themself as native, "just" on a larger timescale. There is no easy solution that I can see. (except letting go of fanatism)
But yes, the question of the "right of return" of Palestinian refugees is a tough one; but I think it's a distraction. The very minimum the international community should force Israel to, is to withdraw within the 1967 border and cease any interference with the territory and sovereignty of Palestinians. It won't happen because the goal of Israelis and Zionists everywhere is to conquer as much land as they can, and a constant state of attrition is the excuse they need to keep settling more ethnically-cleansed land.