Cannot run AppImages on NixOS

[balsoft]

I can run arbitrary AppImages on NixOS with appimage-run tool. But appimages generated by nix-bundle fail:

$ ./nix2appimage.sh emacs
AppImage created at Emacs-x86_64.AppImage
$ appimage-run ./Emacs-x86.64.AppImage
unshare(): Operation not permitted

Even though kernel.unpriveleged_userns_apparmor_policy = 1

[viogq]

failed here as well