Terraform and Kubernetes' StorageClass with node affinity
Well of course its always the same - as soon as you actually do ask for help you figure it out...

resource "kubernetes_persistent_volume" "nodeconfig" {
  metadata {
    name = "nodeconfig"
    labels = {
      a = "a"
    }
  }
  spec {
    capacity = {
      storage = "25Gi"
    }
    storage_class_name               = "nodeconfig"
    persistent_volume_reclaim_policy = "Retain"
    access_modes                     = ["ReadOnlyMany"]
    persistent_volume_source {
      local {
        path = "/mnt/nodeconfig"
      }
    }
    node_affinity {
      required {
        node_selector_term {
          match_expressions {
            key = "kubernetes.io/hostname"
            operator = "In"
            values = [var.config.RGs.Primary.clustervmhost]  # must mnanually put this one in
          }
        }
      }
    }
  }
}


So the docs were a bit off of the lists of lists, it was a map of maps of lists.