Okay, apparantly in some endings with Yes-Man, New Vegas falls into Anarchy, that's the one I get. But there's also one where The securitron army gets diverted to las vegas where order is restored on the streets. How do I get order restored on the streets?

Work for the NCR

In order to create an orderly but independant New Vegas, you must have used the Platinum Chip to upgrade the Securitrons beneath Caesar's camp. Later on, during No Gods And No Monsters, you must choose to use Hoover Dam to boost the control signal over the Securitron army instead of destroying Hoover Dam.