As long as you're on one ticket and get boarding passes for both flights, you would have plenty of time. You can easily make a 30 minute connection at ICN if absolutely necessary (due to delay).

Having said that, I'd call and request a non-stop as another poster suggested. It is a legal connection still, but if you say you're uncomfortable with it, you might get a sympathetic agent who will do it anyway. Plenty of flights from both HND and NRT on NH and SQ.