After retiring as a player at a young age and completing a Sports Science Degree at INEFC Lleida, Nus started his coaching career at Liverpool's academy.

After his time in England and with the end of Benitez's period in Liverpool, Nus moved to the K League with the Chunnam Dragons, where he was appointed as assistant coach under Jung Hae Soung.

In addition, he has worked with Brighton & Hove Albion (English Premier League), Melbourne Heart (A-League), Ghana National Football Team (Africa), Elche (La Liga), Rayo Vallecano (La Liga Smartbank), Rayo OKC (NASL), Irtysh Pavlodar (Kazakhastan Premier League), and Eskilstuna (Allsvenskan).

During this experience, Nus had the opportunity to work with world-renowned players such as Steven Gerrard, Javier Mascherano, Xabi Alonso and Pepe Reina.

After three years in the UK, Nus moved to Asia to work for the Chunnam Dragons in the top-tier division of the South Korea K League.

Nus' integration to the A-League was facilitated by his relationship with Aloisi, who previously played for two La Liga teams, Osasuna and Deportivo Alaves.

The technical director, John Van’t Schip, took charge of the team and Nus was automatically promoted to first assistant coach.

Nus decided to stay as assistant coach of the Black Stars to compete at the 2017 Africa Cup of Nations, which was the 31st edition of the tournament, and was hosted by Gabon.

At Rayo Vallecano, Nus faced similar circumstances as in Elche, as the club was relegated to the Segunda División after finishing 18th in the 2015–16 La Liga season.

With the club's goal to build a roster to return to La Liga, Nus decided to remain at the club and played an important role designing the 17/18 squad, with players such as Fran Beltrán, Roberto Trashorras, Óscar Trejo, Bebé, Adrián Embarba, Raúl de Tomás and Unai López.

On November 7, 2016, following the conclusion of the 2016 NASL playoffs, Nus stepped down and returned to Spain to continue his role as technical director for Rayo Vallecano.

The club signed the Mauritian international Khassa Camara, Ghanaian striker Kwesi Appiah, Belgium defender Benjamin Lambot, Australian Dylan Fox and Guinean Idrissa Sylla.

In addition, the team was able to defeat Mumbai City– owned by the Football City group – in their opening game of the 2020/21 season by 1–0, as Kwesi Appiah scored his first goal of the campaign.

Gerard Nus is the co-founder of Efficiency Match Sports, software designed to organize training sessions, manage teams, create animations, control data and scout players.

Nus has worked for the Catalan TV (Esports 3 / TV3), analysing the Barcelona games from La Liga and the Champions League.