Akkadian

nasābu - to blow away, winnow (CAD N₂ 56, AHw. 758)

In both sources the term is not separated from nasāpu id.

PS
*nšb - to blow (SED I No. 49v, HALOT 728)
Cf. SED I No. 51v&52v (*nšp ‘to blow’ and *nšm ‘to breathe’).