If this doesn’t work, there is the possibility the game is looking for the mods in the documents folder- place here Place/install all mods into, Program Files(x86)/Steam/steamapps/common/Sim City 4 Deluxe/Plugins In my opinion NAM is essential for Sim City 4 as the official game has some significant issues with public transport.
This video will tell you some cool mods to get which can enhance your cities and make things really interesting.
Sim City 4 is an epic game, that is made even better using some mods.
