Across the world, Nikolaiev (Nikolaiev 
, Николаиев 
) is an extremely rare unknown gender forename. Much more prevalently, Nikolaiev is the last name as well as the forename.
Mr, Andrii, Rachel, Daniel, Dmytro, Leonid, Joseph, Nikita, Viktor, Yevhen, Matthew, Michael, Mikhail, Dmitriy, Gregory, Valerii, Oleksii, Mykhailo, Sadimarie, Anatolii, Vladimir, Yevhenii, Andriy, Steven, Serhii, Sergei, Joe, Mike, Nick, Igor, Ihor, Oleg, Oleh, Sadie, Steve, Anton, Alexander, Artem, Pavlo, Peter, Linda, Vasyl, Vadym, Yurii, Marsha, Maksym, Mykola, Sergii, Katie, and Aleksandr