From the beginning, Liz and Nick's relationship on The Bachelor could have been either amazing, based on their history, or catastrophic, based on their history. But with her inability to keep their past hidden for very long, she was her own undoing on the show, which is why Liz's elimination from The Bachelor isn't all that surprising. Still, she should have lasted longer and could have, if she'd been able to keep her mouth shut. But after the first group date, and after hearing the other women go on about their own connections with Nick, Liz felt compelled to reveal her own interactions with him, even if it happened months ago before The Bachelor even began.
In an effort to be honest and to get out the truth, Liz confided in Christen about everything in order to "clear the air and move forward," but it understandably resulted in a bunch of drama. Obviously the truth was going to come out, but for Liz, getting the truth out there sooner rather than later was much more important. You might say that she also felt the need to reveal her past with Nick on The Bachelor because of the way so many of the other women were revealing their physical connections to him, and in a way, you can't blame her.
On the season premiere of The Bachelor, Liz and Nick were able to somewhat talk about their past. But as with most of the cocktail hour conversations, it was rushed and didn't really settle anything. Honestly, it was a surprise that Liz made it to the second episode, considering the way Nick had reacted to seeing her again. And once Nick told the rest of the women about his hookup with Liz prior to The Bachelor, it was necessary. But that didn't make it any easier for him or Liz, and resulted in her elimination from the show in Week 2, even before the official rose ceremony.
In another life, Liz and Nick would have been kind of perfect for each other, as she already seems more than capable of putting him through his paces and they obviously had some kind of connection when they hooked up at Jade and Tanner's wedding in 2016. But since that's all they had, and both Nick and Liz revealed to the rest of the women what went down between them, finding love together was just not meant to be and honestly, Liz probably never stood a chance.