So like I said, all slow growth stuff, where lettuce takes a full month at minimum to grow enough to be fit for harvest, and pretty much everything else takes longer even under optimal conditions. Long term habitation bases and places meant to resist a siege will probably, as noted, have on site production facilities, but quite frankly even during the era of Tiberian Sun GDI was generally considered to be holding the strategic and second strike capacity advantage. Sieges wouldn't really be a thing when their reinforcements could be deployed rapidly and in force.
Nod's unlikely to raid GDI bases for supplies though, unless running far from their standard supply lines and in desperate need of replenishment, or as part of a plan to strike deep into GDI heartlands with a minimal baggage train. And it'd still be risky. Even raiding civilian settlements for the sake of supplies isn't that great an idea given the risk of destroying what you want to get.
Extortion works much better.
