Syntax for adding cors headers when deploying with helm

I am trying to add CORS headers to my binderhub deployment on k8s. Adding them at the root level works for creating a kernel request in the first place, but then I’m unable to send requests to the container that’s booted up. I suspect I’ve got the nesting wrong in the binderhub -> jupyterhub but this seemed to be the way to do it looking at the docs.

Anyone know the correct syntax?

config:
  BinderHub:
      [redacted]
binderhub:
  jupyterhub:
    custom:
      hub:
        extraConfigMap:
          cors: 
            allowOrigin: "*"
cors: &cors
  allowOrigin: "*"