https://www.pcgamer.com/games/after-killing-its-multiplatform-mod-manager-nexus-revives-its-spirit-with-an-announcement-that-its-windows-only-app-will-support-steamos-in-future/
Which means someone else can faff with that version to make it play nicely with your Linux distro of choice.
mod managerkillingmultiplatformnexusspirit