Somewhere in the definition of the Tailscale operator the configuraiton changed from taking a basic-auth formatted secret to needing a customized one. This makes that happen
It should not be necessary to deploy these files as, ostensibly, they are configured to be auto-deployed on the nodes at startup time.
nodes.yaml contains things like annotations for the nodes and other similar hubub that makes the code deploy in a friendly manner.
operator-oauth.yaml includes the secrets that need to be defined before the tailscale operator can be deployed. But, of course, it also needs things like the external-secrets helm chart before it is fully deployed in the proper manner. There is a little bit of a chicken and egg type of problem here, but if you just keep applying everyting, over and over, it will eventually be installed and configured correctly.