To me it seems ridiculous to use someone else's nickname if it's one that doesn't even stem from a real name. I see
Che as being a credible name for the masses to use just as much as I'd think El Greco (nn turned name of 16th century painter Domenikos Theotocopoulos) or Baby (nn turned name of the character
Frances in Dirty Dancing) would make good names, which is not at all.