I literally just started my first nixos an hour ago or so, so I might be missing some obvious things, but whenever I try to enable wireless, the nixos build fails. In Plasma I already enabled wifi anyway but I´d like to have it in sync with my config file.
networking.wireless really is just a name for wpa_supplicant. NetworkManager already manages wireless connection for you, so there’s no need to enable wpa_supplicant (they would conflict with each other). Generally you will want NetworkManager if you use KDE Plasma because it has better integration.