Nikolai's Warehouse is a storage facility owned by Nikolai.
Oswald Cobblepot knew the location of Nikolai's Warehouse and gave the information to Sal Maroni. After that, Maroni sent a group of mobsters led by Frankie Carbone (including Penguin and Gabriel) to the warehouse to dispose of Nikolai and his mobsters. Nikolai and his thugs were gambling when the door blew up and the Italian mobsters shot all of them dead; Nikolai was notably shot multiple times. Later, Frankie decided to add Oswald's body to the corpse pile, since he was jealous of him, but unbeknownst to Frankie, Gabe and the other henchmen were in the pay of Oswald, and they held Frankie's arms while Oswald stabbed him multiple times, fatally.