Part 1/1 of Nod 17: A New Beginning in my C&C Tiberian Sun - Hard walkthrough.
The final act is at hand. GDI will throw everything at you, so you'll want defense fast. There's plenty of Tiberium here, so I recommend at least 4 Harvesters.
They'll send Titans in groups of 6+, Disruptors in groups of 4 and the ocassional Mammoth Mk.II. Thankfully, 6 Artillery, a couple of Obelisks, infantry and your Cyborg Commando will deal with it. The Cyborg Commando will save you here, use infantry to soak up the Titan's fire, and then destroy with the Commando. The level offensively is ridiculously easy to be honest.
Sub APC your Commando to the NW, the first will probably just be to scout the front line of defense at this beacon (which is relatively weak). Retaliate with Ion Cannon and Cluster Missile after he dies and get another one out. This one should clear the sector. Clear the small blockade west of your base and start building some Tick Tanks and Artillery for the eastern beacon. Send your Artillery already defending your base to the Beacon and send the first ICBM here. Send the second to the NW after revealing the path along, a few escorts may be needed if you're worried, but generally it should be ok if your Commando is causing havoc in their base. The third Beacon is easy enough once you've sent your Tick Tank/Artillery force there. It won't need protecting on the way.
Don't worry about the fact that it says I have 5 minutes left, there's another 2 orbits for the Philadelphia to take.