I don't think the soundpacks come as NKS files. (Why shall all developers deliever NKS files? Would the soundpacks be more exspensive if so?)
But you can ask Arturia if NKS file should come with the soundpacks. Arturia could perhaps also answer here.
I have the Komplete Kontrol software, and i dont use it. So i can't tell you much about how to use it.
I can tell soundpack files do not show up in Komplete Kontrol.
NKS compatibility is currently unavailable for Analog Lab 3. And Soundpacks look like to be connected with Analog Lab by Arturia.
Analog Lab as an application is not availble in Komplete Kontrol. The Arturia NKS files you see in Komplete Kontrol is for the individual VC applications.
I can see the technically difficulties in combining Arturias and NI's preset systems, especially with Analog Lab. I don't think i would spend that much time to make this work, if i was Arturia. Arturias preset system exchange presets. In some situations, then how should this be able to work in Komplete Kontrol? How should Komplete Kontrol decide to open AL or the original application, if it's a shared preset? It need a lot of work to make this possible, and not destroy Arturias powerful preset system. And NI have even dished a system like NKS before. The Kore system. Some say it was better than NKS.
What you can do for your presets is to find out how to make NKS files of your presets yourself. You have to be able to do this for your own user presets anyway, to make a system work for your own creativity. That should be NI's responsibility to make this easy. Right?
Have you tried to search NI Komplete Kontrol forum for info about this? I suggest you do.
Personally i'm not a fan of the NKS system. In many ways it's not very user friendly, it can be annoying, and you can only use it with NI's controllers. I even think it's at the time being is a problem to use NI's Machine and Komplete Kontrol together. NI try in generel to make a closed system, where third party developers only can deliever sound content, in a way, where it can't be used for other products than NIs.
If you for example ever wan't to use another controller like for example Arturias controllers, then you can't use NKS files.
All this alone disqualify the product for me.
I hope you find a way that work well for you. But i think you perhaps need to do more work, than you have exspected with NKS. I believe many vendors does'nt supply NKS files at all for anything.
Soory about the long post, but i think there is some things it's important to understand with NKS. It's so easy to blame other vendors than NI.