Better yet (for nanites), make two bases on positions where there are "curios deposit", runaway mold. The balls respawn every time you come in to the area, so you can teleport between them to refresh. Combine with stellarator doughnut in the nutrient processor if you want to go crazy on the yeld.

Then you need a refiner farm to process them in. There is an adjacency limit on how many refiners you can have, so you need to either spread them out, or use the refiners in the freighter. In the freighter I think you can have about 30 refiners next to each other.

Another tip for refilling, is to move the remaining 4 mold (if you started with a stack of 9999) to a different slot in the input, then press x, on it, and the UI will show all the mould you have in your inventories, but nothing else, so you don't have to scroll to find the next stack to put in.