Is nightcore basically the Japanese version of dubstep/Japanese dubstep by any chance?

Though I love Nightcore I'm gonna have to say no. Dubstep has a different sound to it. Though (correct me if I'm wrong) Nightcore does a lot of cover songs in the dubstep area. Like I've heard Nightcore cover dubstep artists like Skrillex but I've also heard Nightcore cover rock and pop like Within Temptation or T.A.T.U.

Long story short, I always thought Nightcore was just a more sped up or pitched up version of already made songs. I could be wrong.

Edit: I looked into it; apparently it started as a subgenre of trance. It's characterized by a sped-up melody, fast rhythmic beats, and always higher than normal pitch.
And Nightcore songs can be created by pretty much anyone who knows how to tweak audio files.

It depends on the song and what someone does to it. Yes, some of them show elements of dubstep. However, the only thing someone needs to do is increase the speed of the original song for it to be considered Nightcore. Most Nightcore songs are changed by speed and pitch.

No, it's not Japanese. Actually, the original Nightcore was the name of an artist group and was a duo from Norway consisting of Thomas S Nilsen and Steffen Ojala Søderholm.

This is a song sung by Cascada. The tempo was changed and it was made so that it sounds like a guy is singing it instead of a girl.