Nestor is a given name, often claimed to be of Greek origin. In Greek mythology it comes from that of the son of Neleus, the King of Pylos and Chloris. The Greek derivation is from a combination of "νέομαι" [neomai] - "go back", and "νόστος" [nostos] - "one who returns from travels".
Another theory makes derivation from Hebrew by combination of "נֵס" [nes] - "miracle", and "תּוֹרָה" [tora] - Torah. It is a well used phrase in religious text of Jewish tradition.