This item is part of the quest Wheel of Fortune. After checking the NCR computer at Camp Searchlight in the NCR storage room, Logan will tell the Courier to go to Nipton to find out about the NCR supplies. After inquiring about the supplies with Boxcars, he will direct them to the hidden supply cave just north of Nipton, inside the cave there will be a package in one of the footlockers. Once acquired, the Courier must return to Logan to continue the quest.
pc ps3 If you take the radiation suit before opening the footlocker you are unable to open the footlocker and get the package. Re-entering the cave may fix this. [verified]