This fight comes down to wether or not Ironman's technopathy works on Nimrod...
Given what Nimrod was designed to be (and his feats of adaptation) and the fact that it was designed with cutting edge future technology, I would think that even in the unlikely event that Ironman's technopathy worked on Nimrod, Nimrod would rapidly adapt against it...
Once Nimrod gets past that hurdle, Ironman loses this fight very rapidly and very brutally...