Nash is an elderly man living in the town of Primm. At first, you can find him at the casino where he and the rest of Primm's inhabitants have fled after a Powder Gangers splinter faction killed the town's Sheriff and took the deputy hostage.
After you restore order by finishing the quest My Kind of Town, he and his wife return to their home at the Mojave Express Building where he functions as a trader. Should the courier choose Meyers as the new sheriff, Nash will offer a discount on all his goods. If instead the NCR takes control, Nash will mention that he has an increased amount of goods due to trade routes from the NCR. However, these goods are more expensive due to NCR taxes.
They Went That-a-Way: Johnson Nash is the man who tells the Courier what their delivery was and all the details behind it. He directs players to Deputy Beagle to learn more on where their attackers were headed. The Courier was also supposed to give the payment for delivering the platinum chip and the NCR war documents from the New Vegas Strip to him. During the dialogue about the package, Nash mentions his strange encounter with Courier #5 in which he rejected the job when he saw that the Courier was next on the list.
My Kind of Town: Johnson will give the Courier suggestions on possible sheriffs of Primm and his opinions on them.
I Fought the Law: Johnson can give the Courier information about the possible NCR attack on the NCRCF.
xbox360pcps3 Nash may not go into his shop after helping Primm gain law causing him to never be able to trade with you. This may be due to repairing ED-E before restoring law to Primm. One solution is to fire and rehire ED-E while in Nash's shop. Another possible solution on the PC is to use the console to Kill and Resurrect Nash. [verified]
pc If you attempt to wake Nash up in order to trade with him, he may become a "floating log" as he moves to his stool behind the counter. You will not be able to talk to him until he arrives there, where he starts to sit down as if nothing happened. (screenshot) [verified]
xbox360ps3 There is a chance that your system may freeze upon backing out of the purchase screen. [verified]
If he leaves the Vikki and Vance casino while there are still Powder Gangers in the area, he may run inside his house and be in a constant "fleeing" state for quite awhile, even if you kill the Powder Gangers. [platforms tag needed]
ps3 If you talk to him in order to trade with him, he will answer you;"Give me a moment to get back to my shop, and i'll show you my stock", but he will do nothing about it. Asking him again will do nothing. This is due to patch 1.07. The only known way to fix this is to delete the patch or simply never finish the quest to bring law back to Primm or wait until just before the end of the game to finish the quest. [verified]