The etymology is quite plausible both semantically and phonetically. We should notice that this is the only case where PN preserves *s after *j- (without changing it to *st); since *j- is reconstructed here only on Nakh evidence, one may think that PN *j- is secondary here, and a reconstruction like *Hansē could be preferable. One should also keep in mind that in some languages there is occasional confusion of the roots *jansē and *jămʒĂ q.v. (which led Balkarov - 1964, 98 - to proposing wrong EC connections for the WC form *śǝ), but in general the two roots are being kept quite distinct from each other. The comparison of WC *śǝ with PK *(s̥1̇)to- 'to snow' (Rogava 1955, 36) seems much less probable. See Abdokov 1983, 105.
Note the frequent recurrence of the (oblique base) suffix *-rV (in PN, several Andian languages and Bezht. azo-ra).