Nickelodeon faces backlash for how they portrayed a teenage Ariana Grande

Ariana Grande began her career on a Nickelodeon, but they're facing heat for the way they portrayed her when she was a teenager.  Ariana Grande's fans are shocked by a video that went viral on Twitter, showing then underage Cat in a rather disturbing scene. Namely, the video is a compilation of scenes from Nickelodeon's shows where Grande acts in a nast…