nvidia is used for question particular to the nVidia range of graphic boards/chips and their drivers. Use it only if you know for sure the problem is not a general graphics board issue (in that case use the tag: graphics)
nvidia graphics cards and on board chips have long been supported with special drivers for Linux.
Use of this tag indicates a specific nVidia related problem, that is not a general graphics board issue (in that case grahpics should be used)
Several distributions include the option to install the non-open source drivers for nVidia boards.
Open source drivers for Linux are available from nouveau.
nVidia also hosts a driver archive