Since NOD vastly outnumbers and outguns GDI by an insane amount a conventional victory is impossible. The GDI Remnants have only one True Way of getting 'Victory'

-GDI has to get a Peace Treaty with Kane. Iceland and a few small parts of Earth are recognized as GDI territory in exchange for ending all hostilities and GDI giving SOME of their tech to NOD!

-As part of the peace treaty, GDI has to fight both Globaltech and the Forsaken

-GDI uses peacetime to build a MASSIVE Space Colony close to Jupiter!!!

NOD Militants vastly outnumber GDI Rangers 20k-to-1. Militants have better weapons, armor, training, MORALE and military experience compared to Rangers

NOD can turn most of Earth's sick and old people into Cyborgs which further extends their Quality and Quantity advantage over the GDI Remnants

Due to controlling most of Earth's factories NOD can just overwhelm their enemies with Drones!!!