Ah, yes, I see now. I think a NixOS configuration is best managed as text, but I can see now how code generation could potentially bridge that gap. I'm not currently confident in the ability of LLMs to do this, but I do think that a kind of "NixOS IDE", perhaps with a some GUI elements and writing to some constrained files is a good idea.

Once upon a time, Snowflake OS was working on this, but I don't think the project is very active anymore.