Some people are so hell-bent on Nesta not being Starborn and not reawakening the Dusk Court that they make some really bad arguments.
"Cassian also had the Starborn tattoo. Does that mean he's Starborn?"
No, canon clearly states that Nesta's magic - not Cassian's - chose the Starborn logo as their magical bargain tattoo, just like Bryce's magic chose the Starborn logo as her burn scar.
"SJM uses an eight-pointed star to signify other things, not just the Starborn! The tattoo could mean something else!"
Yes, except Nesta told Bryce that her tattoo looked just like Bryce's scar, which shows that, yes, there are other designs for the eight-pointed star (for example the eight-pointed star used in the Valkyrie training, which Nesta thought her tattoo was originally tied to), but Nesta said hers looked like Bryce's.
"Nesta doesn't even have Starborn magic!"
Well, obviously, she does, or her magic wouldn't have chosen the Starborn logo. Plus, if Nesta wasn't Starborn, she wouldn't have been able to get the Harp. Nesta has full control of the Trove like Theia had, and she has the Starborn blood connection that allowed her to enter the chamber in the Prison.
"Nesta's tattoo disappeared, whereas Bryce's scar is permanent!"
Hence, the point of foreshadowing. Remember, Starborn doesn't mean anything in the ACOTAR world; it only means something in CC. Might Nesta eventually get a scar similar to Bryce's? Maybe.
"Nesta didn't react to Gwydion and Truth-Teller like Bryce and Az did!"
Aidas said that both weapons were keyed to Theia's power, thanks to her assistance in their Making. It's why Gwydion calls to the descendants of Theia, but only those with her starlight to trigger the power inside the blades. That's why over the time that Truth-Teller was with Azriel and Gwydion was with Ruhn, they didn't show magic because they couldn't trigger them, and because both blades were not united. Since Gwydion and Truth-Teller were Made by Theia, Fionn, and Enalius at the same time, their bond always linked them and they sought to be reunited, as they were in their Making. Az only felt the blades tug toward Bryce - nothing that significant for his character. Since Nesta seems to also be a descendant of Queen Theia, there's a good chance the blades will emanate with magic/be drawn towards her in the next book.
"Bryce said Az was Starborn!"
No, she didn't. She wondered if he may be or (and emphasis on the or) if his wielding Truth-Teller also allowed him to wield Gwydion. Since SJM added the "or," I think that's to show that Az isn't Starborn, but he can wield both blades, just not to the same effect as a Starborn. Remember, both blades chose Bryce over Az when she beckoned for them, so Az definitely isn't Starborn.
"HOFAS proved that Bryce is the sole wielder of the Dread Trove!"
No, it didn't. Bryce said that Nesta seemed at the mercy of the Mask, but Nesta's never had problems taking it off before, so I wouldn't necessarily trust Bryce's narration here. Nesta has worn the Mask multiple times, whereas Bryce has only worn it once. If we want to compare, we can only compare Bryce's first time wearing it to Nesta's, and neither lady had difficulty getting it off: they merely wished it off, and it fell off. If Nesta is struggling now, we should be asking why? Is it because she gave up so much of her power to save Feysand? Is it because the more she wears it, the harder it is to get off? Is it to show her negative emotional state? Or could it merely be that she wasn't struggling to take it off, but Az just needed to convince her that the threat was over? In the Bog of Oorid, Nesta only willed the Mask off after Cass and Az bowed before Death Herself. We won't really know until we get Nesta or Az's POV, but I wouldn't jump to the conclusion that the Dread Trove belongs to Bryce. Nesta even said herself that the Trove answers to her, obeys her, and no one contradicts that claim. If she was really struggling to control the Mask, I would think someone would have pointed that out in the Ember bonus chapter.
"Anyone Made could have entered the chamber in the Prison!"
Not according to canon. Only two characters have ever found and entered that chamber: Nesta and Bryce. No one knew the chamber even existed until Nesta found it. Cassian couldn't enter it and Az was only able to enter because Nesta opened up the wards to allow him. Is there significance to Nesta, and not Bryce, opening the wards for Az? Yes, I think so since Bryce mentioned that as heir to the Dusk Court, the very wards obeyed her. And what do we see in this scene? The very wards of the place obeying Nesta.
We also find out two things from Bryce that challenge what we learned in ACOSF: the Harp was left in the chamber for a Starborn - not a Made individual - to find. Which challenges the entire notion that Feyre or Elain could use the Dread Trove. Queen Theia, Silene, and Helena were not Made, but they could wield the Trove because they're Starborn. The only question is how Briallyn was able to use the Crown, but I think that has more to do with Koschei than her being Made. And secondly, Bryce specifically says that the tunnels, the chamber and the Harp were left for a Starborn to find: someone who could bear the Starsword (gifted to Nesta at the end) and whose starlight would lead them down there (Nesta found the chamber and the Harp, so clearly she has starlight of some capacity in her veins).
"The Dusk Court chose Bryce!"
I'm not denying that, but she didn't reawaken it. I think the point was to show that she could have - being Starborn - but that Nesta - also as Starborn - will be the one to do it since she's the only ACOTAR character associated with Dusk. Remember, Vesperus needed to be killed, and the Prison needs to be cleared out before Dusk can be reawakened. Also, Nesta did mention on her first visit that the land seemed abandoned, like it was waiting to return to its former glory. And that was before Cassian told her that the land may have once been its own court.
I'm sure, at some point, Nesta will release the pockets of magic that the Asteri left under the mountains. Just as it did with Theia, the magic of the earth will unite with Nesta.
"Bryce killed the Asteri on Midgard!"
Yes, but she didn't kill the Asteri on the Dusk Court. Nesta did. And Vesperus needed to be killed before Dusk can be awakened. If Bryce was meant to reawaken the Dusk Court, then surely she would have been the character to kill Vesperus...but she wasn't. Nesta was. Nesta, who has also killed Lanthys, a contemporary to the Asteri and a Prison inmate. Nesta, who the Prison inmates now fear. Nesta's already started clearing up Dusk, so surely she'll be the one to reawaken it.
"Nesta has no association with Dusk Court imagery!"
Yeah, cause that's what's important here. I could maybe buy this as an argument if Nesta didn't already dominate all Dusk Court foreshadowing, but you don't give a character this much association with the Dusk Court only to have a character with more "imagery" awaken it.
"Nesta's definitely associated with Dusk, but she won't reawaken it."
Then why all the foreshadowing? I don't foresee this much foreshadowing for a character merely "associated" with Dusk.
"Nesta's just holding onto Gwydion until Bryce returns to Prythian to reawaken Dusk!"
No, this scene was meant to be symbolic of Bryce recognizing Nesta as Starborn - as the one to reawaken Dusk like Bryce reawakened Avallen. Remember this scene took place after Bryce mentioned that the Harp and the chamber were left for someone like her to find. This scene showed that she recognized Nesta as someone like her - a Starborn, someone who can wield Gwydion and someone whose starlight will guide them to the truth.