How have you installed the plugin? git://kong-dist-kubernetes will always run the latest official Kong image which comes with our bundled plugins but won’t include the Nokia OIDC plugin.
Either make your own Dockerfile that additionally installs Nokia’s plugin, or use https://github.com/Kong/docker-kong/tree/master/customize. You’ll also need to update the kong-dist-kubernetes YAML files to reference your Kong image instead of image: kong