Multiple nfs-provisioner instances can have the same name, i.e. the same value for the provisioner argument. They will all attempt to provision storage for the same class of claims. Only one will successfully create a PersistentVolume. The others will fail and eventually move on.
Multiple nfs-provisioner with different names can be running at the same time. They won't conflict because they'll try to provision storage for their own classes of claims.
Given that multiple instances can have the same name, to scale up or down a set of provisioner pods (or pairs of deployments & services), you simply create or delete pods (or deployments & services) with the same provisioner name.