These sagas are of interest not only in their own right as a testament to the civilization of this lost world, but also because they show striking parallels with the traditions of the ancient peoples who at one time were in contact with the North Caucasus. They have been largely viewed as a relic of the old Iranian-speaking culture of the Scythians, Sarmatians, and Alans, with only passing reference made to Circassian lore (chiefly Dumézil 1978; see pp. 34-49, 146-68). That there is an ancient Iranian core in the various corpora is not to be denied (Dumézil 1934, 1956; Bjazyrty 1992). The name Nart is of Indo-Iranian origin (PIE *ə₂n—(ə)r-, Greek ânér-, Lincoln 1981, 97 and n. 4); Sabine Nerô- ‘strong’ (personal name), Umbrian nerus, Old Irish nert, Vedic Sanskrit nrtama ‘most manly’ (an epithet of Indra), Sanskrit nâ, nár-am (accusative) ‘man, hero’, Avestan nar-, nərə-(gara-) (Pisani 1947, 147, §302), Ossetic nart (Benveniste 1959, 37 and n. l).
I’m not sure what that first r- is doing there, but I’m guessing it’s a typo. [Typo fixed (and some vowels changed) thanks to Angelo's comment; I now realize that Colarusso forgot to close that first parenthesis, before "PIE."]