The version of GNOME Chess we ship is pretty old, version 3.34 has been released, and the commits merged directly on top of it make it work for the Librem 5.
It would be nice to ship version 3.34.0 plus those extra commits, see https://gitlab.gnome.org/GNOME/gnome-chess/merge_requests/12 for more information. We would have to ship at least up to this commit from the master branch: https://gitlab.gnome.org/GNOME/gnome-chess/commit/2622a2e6c02bda295e9608354eab37a53e6cbd52.