You misspelled the model in the title. You said it's an NHK, but it's actually an HNK. No wonder it's been hard to find any information on that unit. LOL.
IDK, maybe I'm missing something but I'm not seeing ANY adapters available to go from the Intel internal USB 2.0 2mm pin pitch header to a standard desktop 2.54 pin pitch header. Surely there must be some otherwise why would Intel even provide those headers, but, it may be that Intel only expects that header to be used with proprietary devices that are provided through them or their partners, and use the 2mm pitch connector.
You may need to contact Intel product support and find out if there are even adapters available and if there are, whether they will work with the device you intend to connect. The other option is you might want to check out the NUC forum where there are certainly folks with a lot more experience using these devices that can probably tell you part numbers off the top of their heads.
https://communities.intel.com/community/tech/nuc/content