There is 2 seperate files on the nexus website, one for Multiplayer and one for singleplayer

You must download these 2 files if you want it to work for both, but when you have it in your "Mod Manager"

make sure you don't have the NR singleplayer mod and NR Multiplayer mod activated at the same time or else the game will crash

(P.S. you must download Mod Manager tool to make this mod work.)