I try to gather as much information about NKS as possible. It is all unofficial.
This information was shared by jhorology:
NKSF file is the only type of RIFF (Resource Interchange File Format). File has 4 chunks inside.
- NISI (Native Instruments Summary Information)
- NICA (Native Instruments Controller Assignments)
- PLID (Plugin ID)
- PCHK (Plugin Chunk)
*naming is my guess.
It seems that first 3 chunks are encoded using MessagePack. PCHK chunk is the only pluginstates.