To pass this mission, you need to build infinite obelisks, then build some buggies and attack bikes and send them in to attack the first Operation center. Then when everything is destroyed, make a strong outpost with strong base defenses. Then you will have to bring down the second one. You need to pass through a small GDI base (almost like an outpost). Destroy every building and capture the GDI construction Yard. Make defenses and start building GDI units. Make a swarm of pitbulls and attack bikes. Then send everything to take the other Centers. When everything is done and you are protecting the centers, send all engineers in. It will be better to destroy GDI bunker entrance to shut them behind their shields. So build some SAM's and protect yourself from aircraft.
Make a large base all over half of the map. You should have five Nod and five GDI production queues. Then build Tier 2 vehicles that can use transport with planes. Send them close to the GDI base so they can stop them from attacking you. Then you have to build a Redeemer and MARV and put a Tiberium soldier and saboteur into the Redeemer. Put a Rocket, Militant, Grenadier and Engineer into the MARV. Then build some mammoths and purifiers and send everything you have. The path should be clear. Send the Saboteur and capture the Tacitus.