When mirroring the NKP bundle to a private registry, the recommended method is to use the nkp bundle push or similar commands with the--to-registryoption, specifying the target registry along with the credentials (--to-registry-username and --to-registry-password).

Key reference from documentation:

“Use the --to-registry flag along with --to-registry-username and --to-registry-password to push the NKP bundle to a private registry.”