[2][3][4] Born in Safrabolis a district of Nea Ionia in Athens, Nikolaidis had also descent from North Epirus, where his father, Ilias left in 1918 during the World War I.
His love for football brought him at the door of the local PAO Safrabolis' youth team, in 1958, where at the age of 14 made his first tryout in order to join the club.
In 1965 Nikolaidis, alongside other players from his club, after a recommendation from Georgios Magiras, was transferred at AEK at the age of 21 and became a regular after his impressive performances in the friendlies.
[6] His 2 goals against Olympiacos on 31 March 1968, won the derby for the club and gave them to a high extend the title at the end of the season.
On 29 September 1972 his goal at the 89th minute gave the AEK the victory over Internazionale with 3–2 for the European Cup, in Nea Filadelfeia.