Nicholai was a Russian gangster and one of the henchmen of Viggo Tarasov, leader of the Tarasov Mob in New York City. He was also one of his security details and is tasked with protecting his son, Iosef.
Alongside Kirill, Kuzma and many other henchmen, Nicholai was responsible to the security of Iosef when he and his friends party in a hot tub in the Red Circle club. He first accompanies Kirill when he visits Iosef at a swimming pool but Iosef states that despite the imminent threat, he is not afraid of John Wick, although Kirill reminds him that he should be.
When John arrives to the club in order to kill Iosef, Nicholai, Kirill, Kuzma and their cohorts hunt down the boogeyman through the club. Although Iosef runs away from the club into chaos, Wick manages to shoot Nicholai in the leg before smashing a bottle on his head and killing him with a head shot.