Nickolas Andrew Sobotka, played by actor Pablo Schreiber, is a well-liked young Stevedore with extensive family connections to the Baltimore port and links to the criminal underworld.
Nick is Frank Sobotka's nephew a dock worker in his uncle's union. He often had to keep his cousin Ziggy out of trouble. Nick was much more cautious and level-headed than Ziggy, a fact his uncle appreciated. He was involved in his uncle's smuggling operation and often served as Frank's go-between in meetings with Spiros Vondas. He would meet with Vondas at the diner which served as the Greek's "office." Vondas would give him the serial numbers of the cargo containers The Greek was bringing into the port, and Nick would convey this information to his uncle.
Nick had a girlfriend, Aimee, with whom he had a daughter, Ashley. They wanted to move in together, but they were unable to afford a place of their own; Nick lived with his parents, and when she spent the night with him, she had to hide from them. Though Nick very much wanted to settle down with her, his lack of steady income led to tensions between them.
Since Nick was one of the younger stevedores, seniority prevented him from getting enough work at the docks. Desperate for cash, he and Ziggy stole a trailer full of cameras, which they sold to the Greek's front man, Glekas. This brought Nick to the attention of Vondas, who asked him if he could procure large quantities of certain chemicals. Ziggy was immediately interested, but Nick was more conscientious, fearing that the chemicals would be used to make bombs. After some research on the internet, he discovered that they would be used to process drugs, and he agreed to the deal.
Ziggy was into drug dealing and invited Nick to join in, but at first Nick angrily refused. Later, when Ziggy's ineptitude nearly cost him his life at the hands of Proposition Joe's nephew Cheese, Nick asked Vondas to intervene. Vondas sent Sergei "Serge" Malatov, who forced Cheese to back off at gunpoint. Sergei then helped Nick negotiate a settlement with Prop Joe himself.
When the two cousins brought Vondas the chemicals he had requested, Nick asked for payment half in cash, half in heroin. Since Ziggy had proved incompetent, he began selling the drugs to local dealers, with much more success than his cousin. He was spotted meeting with the dealer Frog by Herc and Carver, who were doing surveillance of drug dealers near the port. When the drugs he'd received for the chemicals ran out, Vondas put him in contact with "White" Mike McArdle, who became his new supplier of heroin.
Eventually a warrant was issued for Nick's arrest. The police raided his parents' house, shortly after Ziggy was arrested for the murder of Glekas. Though Nick was not home, his parents were aghast when the police found drugs and cash in his bedroom.
Later that day Vondas approached Nick with an offer to help Ziggy, in exchange for his and Frank's silence. The young Sobotka eagerly conveyed the offer to his uncle. Frank told Nick he would go see the Greek alone. Just before the meeting, the Greek learned that Frank had offered to testify against him, and he had the elder Sobotka killed. A grieving Nick turned himself in to the police, agreeing to become a witness against the Greek and his gang. As his uncle had, he refused to incriminate members of his union. When Daniels' detail interrogated him he identified the Greek in a photograph, giving the detail its first picture of its main target.
At the end of season two, Nick, Aimee, and Ashley entered federal witness protection. The last scene of the second season focuses on him looking at the decaying shipping industry from behind a chain-link fence. After shedding a few tears, he walks away on a sidewalk leading uphill. The scene symbolized the season's main theme, the death of work in American industry.