WARNING: The following contains spoilers for Chapter #53, “That's Reality,” of Boruto: Naruto Next Generations by Masashi Kishimoto, Mikio Ikemoto, Ukyo Kocachi, Mari Morimoto and Snir Aharon, now available in English from Viz Media.
The Boruto series really threw fans for a loop when the Karma mark was introduced. Not only did it allow Isshiki to be reborn in Kawaki's body, but it also meant Boruto was going to be a vessel for Momoshiki to return. And come Chapter #53 of the Boruto manga, we're seeing the ramifications of all this, as the alien has taken over the boy and stabbed Sasuke's Rinnegan, making it clear he's going to be the Ōtsutsuki to take over Earth.
However, while it seems like Momoshiki is undoubtedly Boruto's nastiest villain, given the nature of the Naruto franchise and what it's done with so many villains before, this twist could actually make the youngster an even more powerful hero than his dad.
Redemption's a major part of the Naruto world what with everyone from Obito to Orochimaru to Itachi to Nagato garnering it. Naruto, way before he became Hokage, usually found ways to appeal to the light within people so it'd be perfect if his son could carry on that legacy in Boruto. Momoshiki's cutting a bloody path right now but when it comes to forgiveness, Konoha's soldiers are willing to offer people second chances to make up for the past, no matter the body count.
Boruto can offer this to Momoshiki and convince him to rebel against his clan. After all, he's a pawn right now, obediently following the Ōtsutsuki dynasty and overlords that don't treat them like royalty. Momoshiki could come to realize now's the time for him to be his own man rather than just a dog who follows orders. This crusade has killed off his bestie, Kinshiki, and taken out Isshiki and Kaguya, as well, so he shouldn't want to risk his life anymore as part of an unnecessary war that includes deadly space exploration.
Instead, he could be kept within Boruto, just like Kurama is inside Naruto. To this point, interestingly, the Nine-Tails Fox had this same issue wherein Naruto had to convince him to be a brother and not a weapon of mass destruction but ultimately, it proved to be a beautiful partnership with both growing to care about each other. As he's a direct descendant of Kaguya, Boruto's physically ideal for such a mutually beneficial relationship, too, rather than a symbiotic one. Plus, he has the Byakugan blood in him.
Utilizing all of this, he can tap into Momoshiki when danger arises or when more Ōtsutsuki members come, allowing Momoshiki to break the cycle and his predestined fate. This way, Momoshiki gets a chance at life again. And not only that, but seeing as he's an undiluted Ōtsutsuki, when he mixes with Boruto -- who'd also have some of Kurama and Naruto's essence in him -- it'd easily become the recipe for the most powerful shinobi all time.
Boruto would be able to use destructive Ōtsutsuki chakra and he could also hold any Tailed Beast inside him, which would even make the Sage of the Six Paths (Kaguya's son) nervous. But, at the end of the day, what would matter most is Boruto would care about Momoshiki, as well, and help him try to enjoy a free life as much as possible, which is something the clan would never allow.