Nina Soren is an underage prostitute who worked for Johnny Drake's sex trafficking ring.
Background
At an unknown point, Nina became a part of Johnny D.'s sex trafficking ring. She eventually started working for Johnny personally and he forced her to have sex with 15 men for twelve straight hours. Nina was bleeding by the time they were done, but Johnny forced her to take drugs and made her work for another 12 hours. She was eventually sold to one of Johnny's pimps, Timmer. She befriended fellow prostitute Ariel Thornhill and they were about to be bought by Ariel's mother Martha, posing as a madam. Martha gave Nina a phone for emergencies and Nina gave the phone to Ariel. Nina later witnessed Timmer beat Ariel and later sell her to Johnny after he found her talking to Martha on the phone she gave her.
On SVU
Timmer later has Nina work at a Super Bowl party after the rest of his girls are taken into police custody. Timmer sends her over to an impatient john while he waits for Ariel, and Nina grinds on him while they wait. When things start to get hostile, the john pushes Nina off him to try to calm everyone down. Eventually, everyone starts pulling guns and everyone at the party is arrested, including Nina. Detective Rollins later interviews Nina and she tells Rollins everything that happened regarding Timmer's beating and their attempt to leave. When Martha later came in to question her, Nina assumed she was a cop but Martha reveals her status as Ariel's mother. Nina initially doesn't believe her but is eventually convinced. At Martha's urging, Nina reveals that Ariel is in Johnny's underground bunker and gives its location to her. Four girls, including Ariel, are rescued, and Johnny is arrested. Nina is eventually put in a group home while awaiting Johnny's trial. (SVU: "Undercover Mother")
Johnny's trial begins, but several witnesses against him are either killed, deemed unreliable, and lie on the stand. Ariel gives a speech to Nina and several other girls, telling Nina that every one of them is free and Johnny can't control them anymore. She then makes them all promise to tell the truth on the stand. True to their word, all of the girls, including Nina, successfully testify against Johnny. Nina's testimony included her account of working the twelve-hour shift for him. (SVU: "Surrendering Noah")