For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:nm75/openSUSE_Tumbleweed/home:nm75.repo
zypper refresh
zypper install hello
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:nm75/15.5/home:nm75.repo
zypper refresh
zypper install hello
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:nm75/15.4/home:nm75.repo
zypper refresh
zypper install hello