Anyone who thinks Rothbard is more representative of mainstream libertarianism than Nozick is out of their damn mind and spends too much time in the internet libertarian bubble.
Rothbard is more representative of contemporary libertarians based on my experience at universities across the world and major libertarian conferences. This is largely due, no doubt, to the facts that (a) many recent libertarians came to learn about libertarianism on the internet (e.g. Mises.org) rather than through the syllabi of political philosophy departments and (b) academic libertarians have been moving sharply in the anti-state direction and away from minimal statism for the last 40 years.
Not to mention the fact that Nozick himself had two if not three distinct takes on libertarianism in his lifetime.
In a way, Nozick is not representative of himself, much less the “mainstream” of an entire political movement.
I think F.A. Hayek and Milton Friedman are more representative of the philosophical “mainstream.” As a Rothbardian myself, I’m happy to see that Mises and Rothbard have gained a lot of ground in recent years.