Unfortunately, the original Need for Speed: Underground 2 game does not support split-screen multiplayer on PC. The game's developer, EA Black Box, did not include this feature in the PC version, likely due to technical limitations and the focus on online multiplayer.
NFS Underground 2/Prostreet - Local split-screen multiplayer? need for speed underground 2 pc split screen
Because the PC version natively supports LAN play for up to 6 players, you can "fake" split-screen by running two instances on the same machine using or a similar tool. Unfortunately, the original Need for Speed: Underground 2
: You will need at least two controllers (e.g., Xbox or PS4 controllers) as keyboard/mouse sharing between instances is difficult to set up. Because the PC version natively supports LAN play
There is no official patch. There is no toggle in the settings menu. However, through a combination of third-party software, virtual machine wizardry, and community patches, local co-op is achievable.