Tiller: dial tcp 127.0.0.1:80: connect: connection refused

It means your server: entry in your .kube_config.yml is pointing to the wrong port (and perhaps even the wrong protocol, as normal kubernetes communication travels over https and is secured via mutual TLS authentication), or there is no longer a proxy that was listening on localhost:80, or perhaps the --insecure-port used to be 80 and is now 0 (as is strongly recommended)

Regrettably, without more specifics, no one can guess what the correct value was or should be changed to

I am sure that there is a need to set up Kubernetes provider on your terraform configuration. Something like this:

provider "kubernetes" { 
  config_path    = module.EKS_cluster.kubeconfig_filename
}