I dont think the switch can remotely activate the joycons so I dont think you could use the switch to find the joycons.
On the other hand for the joycons to be able to find the switch, you would have to have something running constanly in the background on the switch that you could trigger with a key combo press.
One of these may not be possible and the other isnt very practical.
If you really wanted this maybe a module that makes a max volume noise when the lock screen is activated so that you could find the tablet by waking it up with a wirelessly connected controller. But it would be annoying as hell in all other cases when you see the lock screen.