Too bad it was in the sidewall. They flex too much for a plug to hold. But for only a few bucks risk it’s worth trying one.
If it doesn’t work, replace the tire. Don not use Slime or and other goo, as they’ll squirt out the valve when you adjust the pressure and gum it up, and they leave so much mess that lots of shops won’t work on wheels with that stuff in them.
I doubt that anyone anywhere will not recommend against the use of a tube. It’ll change the tire’s handling and performance characteristics to where it may be unsafe.