<div style='font: 10pt Arial; text-align: left; '>Run TOWARDS him. Yeah, towards. Even if he's running right at you. Nemesis usually tries to hit you with only one of his arms--can't remember whether it's his left or right--so run at the side he doesn't swing at you with. If it's his left, run at his right; if it's his right, run at his left. I wish I could remember which arm he uses, but it shouldn't be too hard for you to figure out.
And this is obvious, but don't try to fight him in a narrow corridor or anything like that. Lure him into an open area and try to run tight circles around him, stopping to fire everytime he swings and misses. And for god's sake, don't let him pick you up, since that does major damage. His running punch looks nasty, but it doesn't do nearly as much damage as you'd think.
I know there's a FAQ on Gamefaqs that has a lot of great pointers about how to fight him, so you might want to check there.</div>