There's no foreshadowing about Nora.
Bitching about Nora's optional cheating is moot, since intimacy and attention in relationship is essential. If you deny it to your LI then eventually he/she will seek it elsewhere, it's all on you. You can't just stop feeding your dog and then complain that it steals your food instead of waiting for you to feed it once a year, that's just stupid. I'm not the one to defend cheating hoes, but Nora was absolutely justified in doing so. Also, it was made to not blue ball player for too long if you pursue Nora.
Chloe and Nora don't actually hate each other. They have issues with each other, but also want to improve their relationship, as they mentioned on couple occasions. Mismatch of personalities aside, Nora's shitty romance and Chloe's way of handling things affect their relationship. I expect them to improve their relationship after Nora's break up and Chloe's potentially losing to Lindsey.