NSLookup a csv list of Hostnames

$servers = get-content "path_to_the_file"
foreach ($server in $servers) {
  $addresses = [System.Net.Dns]::GetHostAddresses($server)
  foreach($a in $addresses) {
    "{0},{1}" -f $server, $a.IPAddressToString >> C:\IPHOSTNAMEOUTPUT.txt
  }
}