I would suggest that Nuko might be a version of the Hebrew name Nachum (sometimes Nuchum). There are also related names like Nachman and Menachem. The root of all these names means comfort in Hebrew. If I'm right then the name Nuko was more of a nickname or Polish name but a formal Hebrew name like Nachum would have been used on a gravestone etc.
SPIELER Lodz, Zloczew, Belchatow
SEGALL, SCHWARTZ Piatra Neamt