not 100% you wont get an error msg, only way to be sure is get a new one from ebike shop for 50 quid.
eddie pj has had both so guess he will know for sure.
but it does look like you need the nyon remote or get a 414 error ;(
I know for 100% that the Intuvia control won't work with Nyon, as I tried to fit Nyon to an Intuvia set bike.
What I can't remember and probably never even tried, is whether you can simply press the Home switch on the Nyon Display, then use the toggle switch to navigate to the power settings.
As SW has said, you are just going to have to buy a new Nyon specific switch.
The control switch is just plug and play to the console base, so you shouldn't have to buy the switch and console as a complete unit.
If you aren't using Nyon settings, I'd sell it and fit Intuvia.