For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:joeyli:branches:Virtualization:bsc1205588_NX/openSUSE_Tumbleweed/home:joeyli:branches:Virtualization:bsc1205588_NX.repo
zypper refresh
zypper install shim
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:joeyli:branches:Virtualization:bsc1205588_NX/15.5/home:joeyli:branches:Virtualization:bsc1205588_NX.repo
zypper refresh
zypper install shim
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:joeyli:branches:Virtualization:bsc1205588_NX/15.4/home:joeyli:branches:Virtualization:bsc1205588_NX.repo
zypper refresh
zypper install shim