Ok, based upon our current tech and seeming want to pay the US back a little for their attacks on us, I'll daw a plan based around defense with long-range attacks on their military bases and industry.
Phase 1: Using our nanites, we fab up enough tanks and BMPs/BTRs to arm up our regulars, and enough weapons to arm our conscripts. We also fab up a bunch more Thorium reactors to provide power for later operational phases.
Phase 2: After prototyping and testing is complete, we begin deploying 1st gen railguns and lasers, and potentially our Very Large Detection Array (If it is both feasible and easily deployed)
Phase 3: We begin working on an intercontinental rail-launcher designed to be able to hit with only a 10-100m deviance, if necessary using guided munitions, and hollow out a mountain to serve as a firing point.
Phase 4: Hopefully by this point 2nd gen lasers are arming our aircraft and we're beginning to phase in railguns on our conventional army, but if we aren't, oh well. Operational Phase 4 is the targeted destruction of US military bases and industrial centers with our new ultra long ranged rail-artillery. After we begin, we demand the US surrender to us, and begin moderating peace talks.
This is a VERY broad plan and is based upon us being ignored. This is NOT a worst case scenario plan. This is a general operational plan based upon simply holing up to get our new technology online to a point where we can strike at our foes with impunity while not being struck back. With the US currently busy, the most forces I think we can expect in an attack are a US CBG and MEU, alone, perhaps with airlifted army support if they gain a beachhead. I'd recommend nanite tower constructed along the shoreline ready to terraform our coastline in a defensive wall that would make Normandy look like a frolic.