The concept of individual rights surely came from the modern milieu, which means it had many causes, and in the early modern period thinkers might have been liberal in some respects and traditional in others because these issues were still being worked out. Hence, Selden and the other conservative forerunners of this nationalist version might have picked up on the earth-shaking changes that had recently happened or that were in the offing such as the Black Death, the Reformation, the discovery of the New World, the rise of the merchants, the Scientific Revolution, and so on. But I don't think the question of the exact origin of some concept is quite as relevant as whether the concept currently sits well with a certain political stance like conservatism.

Hazony may just be appealing to individual rights to cover his bases, or to avoid alienating libertarians. Whether this form of conservatism is logically viable seems to me the fundamental issue.

You seem to agree with Hazony about nationalism. I say a lot more about nationalism in an upcoming article on Russell Vought's Christian nationalism. The concept is evidently slippery and is in flux, but to avoid trivializing the concept, Britannica's definition should be kept in mind. Nationalism is an "ideology based on the premise that the individual’s loyalty and devotion to the nation-state surpass other individual or group interests." Nationalism, then, transfers group identity from an association with ethnicity, an aristocracy, the native soil, or some traditions to the secular political abstraction of a nation.