For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:zzndb001/openSUSE_Tumbleweed/home:zzndb001.repo
zypper refresh
zypper install mozilla-nss-certs
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:zzndb001/15.5/home:zzndb001.repo
zypper refresh
zypper install mozilla-nss-certs
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:zzndb001/15.4/home:zzndb001.repo
zypper refresh
zypper install mozilla-nss-certs