Big Nog probably has a better ground game and he has more technical stand up, so this should be a favorable matchup for him, although.. He's actually not that fast so out pointing Roy on the feet all night won't be that easy considering how battle worn he is. If he can't get out of the way of Roy's heavy hands consistently, he could be in for a rough night.
He needs to turn this into a grappling match in my opinion to be safe. Only needs to use his technique standing to close the distance so he can get ahold of Roy. Who has the advantage in the clinch, though? Could Roy throw his weight around to handle himself there? It's not like Big Nog is that big.
Psalm 30:5 "For his anger endureth but a moment; in his favour is life: weeping may endure for a night, but joy cometh in the morning."
Top 3 Favorite Fighters
1. Chuck "The Iceman" Liddell
2. Glover Teixeira
3. Demian Maia