If you program your Nanite to do something like information gathering, then it'll need a server to keep all that information in some form of memory storage.
Besides, you can also use your brain as a makeshift server for simple stuff but not overly complex, Nanite is something you need to program to follow your will or whatever otherwise, It probably won't work.
With manipulation, you can control them consciously but by programming them to follow your thought you don't need that, right.
As for "Nanite generation" I think you need an example Nanite to generate more of them.
Well, you could generate Nanite yes, but they'll be empty with no program put inside of them, since you don't have a schematic of Nanite or know how they work.