Obtain a Nuclear Keycard
To launch a nuke, you must first obtain a nuclear keycard. Since you earned the rank of General, you have access to a number of tools to help locate on through the Enclave. Accessing the Surveillance System Terminal In the east corner of the room will give you a number of options to locate the necessary parts to launch a nuke but the first one you will want to locate it the Nuclear Keycard Escort. Once you initiate this search from the terminal, you will get a marker on your map with the location of the escort.
Try to track the escorts movements so you take the best path to intercept it, as the marker will constantly move, following the moving escort. Take down the escort and you will be rewarded with a nuclear keycard.
Uh, what room? Where? This isn’t really helpful