Just a quick guide for people that want to use shadowplay on Fivem, here are the steps how to make it work:
1) to make ShadowPlay on, you need to go to Nvidia GeForce experience app, go to settings and make In Game Overlay enabled.
(To open shadowplay overlay in game press Z and CTRL)
2) Open shadowplay overlay in game (press Z and CTRL) and go to settings, press privacy control on the bottom of the list and allow desktop capture.
2) To make ShadowPlay working on FiveM you need to go to Fivem application data folder.
3) Find and open CitizenFX file using notepad which is located in Fivem Application data folder.
4) After opening the file using notepad type DisableNVSP=0
5) save changes by pressing CTRL and S together.
It should start working now!
I wanted to add photos for the guide so that it will be easier, but max size of photos that I can upload on this topic for some reason is 4.77MB.