I switched to NixOS recently and am basically running the default configuration with GNOME on wayland. I have noticed however there are quite a few issues with running app-launchers.
I’ve so far tried Ulauncher, wofi, bemenu, sirula and rofi-wayland, and none of them will actually display. Well, apart form wofi, which can only display in the ‘normal window’ mode.
This seems to be caused by the compositor not supporting the wayland layer-shell protocol. However when running some of these apps on GNOME Ubuntu, there were no issues. This makes me think there might be an issue specific to NixOS.
A lot of the solutions to similar issues online suggest to enable specific parts of xdg.portals, but this doesn’t resolve the issue. Setting XDG environment variables also didn’t resolve the issue for me.
I’m not experience enough to say if it’s a NixOS issue or a configuration issue, but since I use a basically stock-configuration of NixOS I suppose it is an issue regardless.