Chris_TR [1] filed a deletion request for nx-all [2]:
The package has been outdated for a while and although it's not
orphan, it hasn't been updated since it got adopted. Per the notice at
the top of https://wiki.archlinux.org/index.php/FreeNX , it's not
supported and it's been replaced by X2Go.
[1] https://aur.archlinux.org/account/Chris_TR/
[2] https://aur.archlinux.org/pkgbase/nx-all/