Nuking the Bar on C&C_Field.mix map is very easy. Simply buy a nuke and run behind the first rock on the left. If you got there, then stay until the AGT's missle hit's the rock you are hiding behind. After that run to the behind the next one (Don't jump because the AGT may hit you more). After you get there, plant the C4, and then the nuke; or place the nuke first. Run back into the tunnels and watch as a nuke blows the Bar.
If the enemy catches you and tries to disarm the Nuke then protect it with your life, and if your lucky, you might have bought enough time for your c4 to go off and kill all the ones near the nuke.