Is metaphysical nihilism an answer to “Cogito, ergo sum”?
Well I want to say neither. I don’t see what it has to do with it much. However, if anything, Descartes’s Cogito would be immune from it because the Cartesian soul is not a concrete object. It is immaterial and extensionless, more like an abstract entity, which is permitted by metaphysical nihilism. If you notice though, at the start of Descartes’s Meditations, the state of the world that MIGHT be the case, is metaphysically nihilistic, because everything in which one can doubt, is assumed to be false. Therefore there might not be any material objects whatsoever. It is only all the way until Meditation 6, that the external world is proved to exist.