2009-10: Richard Nejezchleb played for the Slavia Praha U18 and U16 teams in his hometown of Prague and skated for the Czech Republic's U16 team. He scored 5 goals with 14 goals and was +6 with 14 penalty minutes in 36 games (including four playoff contests) with the Slavia U18 team. He scored 9 goals with 7 assists and was +10 with 48 penalty minutes for Slavia in eight U16 games. Nejezchleb scored 1 goal with 6 penalty minutes in three international games for the Czech U16 team.
2010-11: Nejezchleb played ten games for Slavia Praha's U20 team as a 16-year-old and was one of the top forwards in the Czech U18 league. He played nine games in international competition for the Czech Republic U17 team. Nejezchleb scored 1 goal with 7 assists and was +5 with 4 penalty minutes in ten games for the Slavia U20 team. In 36 regular season games for the club's U18 team he scored 22 goals with 16 assists and was +14 with 56 penalty minutes. In three playoff games he was -3 with 1 goal, 1 assist and 31 penalty minutes. Playing for the Czech U17 national team he scored 1 goal with 4 assists and 4 penalty minutes.
2011-12: Nejezchleb represented the Czech Republic at the 2011 Ivan Hlinka Memorial (U18) Tournament and was the fourth-leading scorer for Slavia Praha's U20 team. In 25 domestic games, including one playoff contest, he scored 11 goals with 12 assists and was +16 with 14 penalty minutes. In four games at the Ivan Hlinka tournament he was -5 with no points and 2 penalty minutes. In three games with Slavia Praha's U18 team he scored 4 goals with 2 assists. Nejezchleb was selected by the WHL's Brandon Wheat Kings in the first round (35th overall) of the 2012 CHL Import Draft. He was ranked 41st amongst European skaters in Central Scouting's final rankings but was not selected in the 2012 NHL Draft.
2012-13: A shoulder injury in the first half of the season and a lacerated finger in January limited Nejezchleb to 35 games with Brandon in his first season in North America. He scored 11 goals with 13 assists and was +3 with 34 penalty minutes on a Wheat Kings team that finished last in the East Division and missed the playoffs.
2013-14: Nejezchleb skated in 66 of 72 games for Brandon and was the leading goal scorer for the Wheat Kings in his second WHL season. He scored 32 goals with 25 assists and was -12 with 75 penalty minutes. Brandon finished third in the East Division and advanced to the second round in the playoffs. Nejezchleb scored 5 goals with 4 assists and had an even plus/minus with 13 penalty minutes in nine playoff games. In his third year of NHL Draft eligibility he was ranked 50th amongst North American skaters in Central Scouting's final rankings.