When you reject the idea of reductionism, which Nagel's paper provokes us to do, then the entire idea of emergent phenomena collapses. Everything is on the same level, from fundamental particles to consciousness. Of course, some things can still be reduced and others can't, but in no situation is a phenomenon reduced in its metaphysical status. So what's the "problem" again, exactly? Consciousness doesn't need to be explained in terms of objective facts—it's not a special metaphysical thing but merely a theoretical term like anything else.