With the following, you can create a 3-node NATS Server cluster:
kubectl apply -f https://raw.githubusercontent.com/nats-io/k8s/b55687a97a5fd55485e1af302fbdbe43d2d3b968/nats-server/leafnodes/nats-cluster.yaml
The configuration map from the NATS cluster that was created can be found below.