If you"re missing the Nvidia settings icon in your system tray and want it back there's a registry fix I found on the Nvidia forums open regedit and go to Computer\HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\nvlddmkm\NVTray enable ShowInSedona and StartOnLogin by doubleclicking and changing 0 to 1, then right click on desktop and select Nvidia Control Panel to open, at the top select Desktop and select Show Notification Tray Icon and reboot
This was an issue a few years back. I have the reg. file saved but since newer versions of GeForce Experience this hasn't been an issue. They fixed it so the icon is back. Mines there..
There's still an issue with it not showing up on Win10 and the fix is the one I posted, the two registry entries are in a different place from what your talking about, mine wasn't visible and had no option to display tray icon until I applied the posted fix, I had all the latest updates to Nvidia and Win10. I had tried your fix " registry" and other 2017 fixes but none worked except the posted fix.
Ya seems strange, after I did the 1809 Win update from 1803 now that I think about it I had the issue, so maybe that was the cause, oh well computers got to love them, cheers