**** END GAME SPOILERS*****
To get the Achievement All or Nothing, you will have to complete the game aligned to Mr.House. After fighting your way through Hoover Dam you will have to go to Legate's Camp. After killing or convincing Legate Lenius to surrender and then shortly after killing or convincing the NCR military leader to surrender <-- (You will need to have 100 speech for this). Mr.House will come up to you and declare that you have won the battle for him, after the short conversation with Mr.House the achievement All or Nothing will unlock.
If you are having trouble with the quest All or Nothing head to this link http://fallout.wikia.com/wiki/All_or_Nothing
All credit goes to Fallout Wikia for the walk through of the quest.