Setup Notification to myopenhab Cloud via NG Rules

Do you mean the UI rule editor? If so, this is currently not implemented. You have some options though…

  1. Use scripted automation rather than the UI rule editor
  2. Use the ‘execute a given script’ Action, which is basically #1 but as a ScriptedAction

Either way, you can use the new rule engine, scripted automation, Jython, and the helper libraries to do something like what is documented here… Actions — openHAB Helper Libraries documentation.