I can't stand Chris and Nora is my favorite LI.
But in that case i have not much sympathy for her.
First, Chris didn't hit her. He pushed her, a bit too strong yes, but not intentionally, neither did he try to hurt her.
Second, he stated 2 times that she should keep her hands off, to which her answer was, she does whatever she wants and continued pulling his shirt... so i think pushing her away is more than justified.
I must admit I lean more towards this opinion. Pushed (not hit), and justified; though he pushed her too hard, no doubt fueled by adrenaline. I do not believe he had any intention of hurting her.
Either way this was essentially a death knell to the relationship.
In my playthrough, I chose to go with any opportunity to be there for her while in Europe and was obviously building our relationship further. Though, i did not have sex with Nora in Europe, despite my increasing attraction to her, simply because I didn't want to the be the reason she cheated. I wanted Chris to the be the (only) bad guy in that relationship. But after she dumped him in this last chapter, I wasted no time to give her what she'd been missing. It was marvellous.
Now however I'm torn because I've truly fallen for Riley since the first chapter (bummed we cannot make her "girlfriend" status yet), I'm enjoying the Aubrey friends with benefits along with Riley. But now my heart is being pulled between Riley and Nora. But matters of the heart are usually complicated and dangerous.