So there is an old debate on whether nicrosil stores Investiture, like stormlight, or the ability to use it. The Coppermind's page contradicts itself, with the books themselves supporting the Ability to use it, and much more. However, the Coppermine claims a necrosis compounder would have infinite investiture and cites this wob (below), which, very notably, doesn't say this. It's just Yulerule asking if a necrosis compounder could compound enough to make Nightblood and Brandon say, "So much," which is true for every compounder. That does not support a claim like "A nicrosil Compounder would be able to use nicrosil to have a nearly infinite supply of stored Investiture."
Now, it's possible I've missed something, but it seems this wob and the idea that it feeds off of don't have very strong textual or WoBual (?) evidence and should probably be moved to speculation.