I don't ship nickvacktor but there is something about them that reads as terribly obsessed with each other....
Like there was a point it stopped being about revenge and just started being about Red.. especially when Nick hesitated to shoot him, when the entire goal was to kill Red......
His life in the past few years had revolved around finding Red, that was a constant, finding and stopping Red - but when he finally had the chance? He hesitated. Because once he pulled that trigger, one of the only consistent things in his life would just.. be gone, over.
He didn't hesitate like that with anyone else, I think..
I don't ship them, they're definitely not romantic or anything close to it, but they're obsessed with each other and that has some strange undertones...