2010-11: Nikita Zadorov skated for the CSKA-Moscow U16 and U17 teams and played for Russia in the U16 Four Nationals tournament. In 45 games he scored 5 goals with 22 assists and had 62 penalty minutes. In five games in the Russian (U17) championship he had 2 assists and was plus-four with 4 penalty minutes.
2011-12: Zadorov played for CSKA-Red Army in Russia's MHL (U22 minor league) as a 16-year-old and represented Russia in the U17 World Hockey Challenge and 2012 U18 World Junior Championship. He scored 2 goals with 4 assists and was plus-20 with 63 penalty minutes in 41 regular season games and in eight playoff games was plus-two with 8 penalty minutes. He skated in six games at the WHC and had 3 assists with 12 penalty minutes. In six games at the U18 WJC he scored 2 goals and was plus-four. Zadorov was selected by the London Knights (OHL) in the 1st Round (ninth overall) in the 2012 CHL Import Draft.
2012-13: Zadorov was one of the top defenseman for a London Knights team that finished with the Ontario Hockey League's best record. In 63 regular season games he was plus-33 and scored 6 goals with 19 assists; amassing 54 penalty minutes. Zadorov was a candidate for Russia's U20 team but was not selected for the team that competed in Ufa. He was ranked 30th among North American skaters in Central Scouting's mid-term rankings prior to the 2013 NHL Draft, and 22nd in the CSS final rankings.