If any kind of pcg to nki conversion is possible, it would be export between Korg Triton audio banks (.pcg) and NI Instruments samples (.nki), which can be difficult to manage as a direct conversion.
You can of course find dedicated converters for audio samples, for example Translator Professional can be used for this. A viable alternative is to use one of the exchange formats in order to transfer the designs.
Updated: November 6, 2023