Jaune killing the Nuckelavee. In the original timeline, it took an entire team RNJR to beat the thing. Jaune doing it essentially on his own while protecting the nearby civilians firmly establishes just how much more ofa badass he has become.
Jaune's first mission with the Specialists is a journey into an underground mad scientist lair where Merlot was creating Cyborg Grimm, and involves blowing the place sky-high and a surprise boss fight against Tyrian. Moment of Awesome at its finest.
In her match against Pyrrha, Emerald manages to get the upper hand through creative usage of her weapons, using her chain to jam Pyrrha's weapon.
As her personal trainer, Jaune notes that Yang is even stronger than she was in canon at this point, and that when the time comes for her first year at Beacon, she could probably beat her canon self at that point.
Chapter 40: Raven arrives as a one woman cavalry for Jaune in a curb stomp slaughter where nobody manages land a single hit, even forcing Hazel to retreat.
Chapter 44: Weiss and Whitley take advantage of Jaune allowing them a few minutes to prepare by summoning dozens of white Nevermore to both hinder his mobility and blind him. While Jaune still beats them, they do force him to fight more seriously than almost anyone who isn't in Salem's group.
Jaune has had a lot of butterflies come off from his actions, but one he probably didn't expect is that Raven is now training his counterpart from this timeline, two years before he was set to enter Beacon.
Chapter 54: Raven shows up at Watts' hideout Maiden-powers-blazing with every intention of killing the man and rescuing Ren and Nora after witnessing Jaune's memories of them and inadvertently forming a bond with them as well.
In a bit of Awesome in Hindsight, Young Jaune manages to stab the rogue Maiden through the thigh when she lets her guard down around him. If that wasn’t cool enough, it's later revealed to be Amber, who has been the Fall Maiden for years at this point.
Chapter 66: Jaune utterly tears through the White Fang in order to save Winter from them, quickly turning a hostage situation into a Mook Horror Show. He was so terrifying that Sienna doesn't even consider him a human, but a monster.
The chapter ends with Jaune and Hazel preparing to fight one-on-one in a battle to the death amongst the flames and corpses of Jaune's rampage.
Tyrian truly proves his combat prowess during Emerald's capture sequence. He defeats Roman and Neo without any visible injuries and then proceeds to go toe to toe with Summer. He then defeats the huntress through sheer viciousness of his attacks and would have killed her if not for Emerald's intervention.
Emerald's intervention deserves a mention. Rather than try to fight Tyrian directly or use her Semblance against him, she capitalizes on the fact Tyrian needs her alive and impales herself, forcing Tyrian to release both her and Summer so the latter can get her to a hospital.
In Chapter 87, Jaune successfully fights Amber to a standstill.
In Chapter 145, Jaune successfully manages to track down ArthurWatts with around 15 minutes left to Jaune to find him before he sends the city of Argus "back to the Stone Age" as he calls it.
Chapter 146:
When the aircraft containing Jaune, Harriet, and Arthur is shot down, Jaune splits off, then Harriet is ambushed by a Maiden and Watts is captured. Jaune tells Ironwood that it must have been the Summer Maiden - and the next scene reveals that it was Raven, as Jaune had figured out Ironwood wouldn't leave him alone with Watts, so he had Raven shoot down the aircraft to capture him.
This is followed up with Jaune revealing to Watts that he has figured out how to use Salem's mark on his hand to steal Watts' soul, just like Watts did to Winter, and he slowly and painfully steals Watts' soul from his body. As brutal as it is, Watts deserves every second of it.
