The squatters want a deal. You help them become self sufficient and they'll give you access to the vault.”— Chosen One to President Tandi
Complete Deal with NCR is a quest in Fallout 2.
As a formality, this quest only requires that you talk to President Tandi, informing her that the squatters at Vault 15 will cooperate with the NCR, and accept their presence. The end results being, Zeke gets a spiffy new house, the squatters get a life (food and water), and the NCR launches its expansion campaign in Northern California.
If you work out the deal, you will receive a $6000 reward from the NCR, instead of just $500 for getting the computer parts free-of-charge.
After completing this quest, Zeke will ironically say that he hasn't got enough food to survive, even if the NCR helps the squatters.
Sometimes, even if you made a deal with NCR and you delivered the computer part, you will still just get $500 instead of $6000.