8.3.32-Namo hRusvAdachi NamuNN nityam
...............
This is one of the consonant sandhi sutras.
When a 'Nam' is preceded by a short vowel and is succeeded by a vowel, always add the augment 'Nam'.
This sutra can usually be identified by the duplication of the nasal (preceded by a short vowel) as shown in the following illustration - but can be confused with the 8.4.45 sutra.
The following illustration shows the derivation of an example shown below:
BG 2.10
prahasanniva ⇐{8.3.32}
prahasan iva
BG 2.10
Underlying: tam uvAcha hRuSHIkeshas prahasan iva bhArata , senayos ubhayos madhye viSHIdantam idam vachas .prahasanniva