You could do something like this:
 
foreach ($c in get-content filerlist.txt){connect-nacontroller $c -cred $cred;invoke-nassh "software get http://<http server>/<ontapversion>.tgz"}
 
 
If you're in a Windows environment and don't have an HTTP Server available, Install IIS  > World Wide Web Services on a server or workstation.  Place the .tgz file in C:\inetpub\wwwroot\