Reconstructions

PCS
*nˁm - (to be) good (Kogan 2015: 194)
PCS
*nbg - to spring up (Kogan 2015: 299)
PCS
*nagd- - bosom, breast (SED I No. 195)

Problematic; scarce attestation in Arb. and Eth. only. 

PCS
*ngw - to go out, away (Kogan 2015: 327)
PCS
*nγṣ̂ - to shake (Renfroe 1992:62‒64; Kogan 2015: 320)
Ugr-Arb exclusive isogloss
PCS
*nḥl - to inherit, to possess (Kogan 2015: 216)
see also *niḥl-at- Note that the root seems to be missing from Aramaic.
PCS
*niḥl-at- - inheritance (Kogan 2015: 216)
see also *nḥl - to inherit, to possess
PCS
*naḥ(a)r- - upper part of chest (SED I No. 196)

Scarce but reliable attestation in South Sem. area.

PCS
*nḥt - to go down (Kogan 2015: 330)
PCS
*nḳm - to take revenge (Kogan 2015: 216)
PCS *nḳm ‘to take revenge’ is clearly related to Gez. ḳim ‘revenge,’ taḳayyama ‘to take vengeance’. Probably, n- in the CS forms represents a fossilized reflexive marker (Nöldeke (1910:180)).