Likewise or similarly in other lexica: see the references at Photius nu7 Theodoridis.
The combination nai\ mh/n seems to occur rarely in classical poetry; Denniston says in Empedocles fr. 76 "nai\ mh/n can hardly stand," preferring kai\ mh/n (for which see kappa 1167): The Greek Particles p. 331, p. 352. It becomes frequent in later poetry (Nicander, Oppian) and prose (especially Clement of Alexandria).