On 12 July 2023, Mumbai City FC announced that they had signed Yoëll on a two-year deal, following his release from Puskás Akadémia FC.[2] He made his debut for the club in the 2023 Durand Cup in the club's first match of the tournament, versus Mohammedan SC as a substitute.[3] In the club's next match vs Jamshedpur FC on 8 August 2023, he scored his first Mumbai City FC goal with a half-volley from a corner, the fourth goal in an eventual 5-0 victory for Mumbai.[4]
He made his ISL debut in the club's first match of the season, away versus NorthEast United FC on 24 September 2023. He played 68 minutes in midfield until he was replaced by another new signing, Tiri.[5] In the club's first home ISL match of the season versus Kerala Blasters, Yoëll was shown a red card alongside Blasters player Miloš Drinčić for their part in a fight during injury time at the end of the match, which concluded in a 2-1 victory for Mumbai.[6]
On 12 March 2024, Van Nieff scored his first ISL goal. After Akash Mishra won a penalty in first-half stoppage time, Van Nieff stepped up and scored. This penalty was the third goal, in an eventual 4-1 win for Mumbai City.[7] This match was exceptional for Van Nieff, as he also got an assist for the first goal of the game with a pinpoint aerial pass to Vikram Partap Singh.[8]
Van Nieff won his first trophy in India at the end of the season, winning the ISL Final over Mohun Bagan to win the ISL Cup. However, van Nieff was suspended for the final due to yellow card accumulation[9].
2024-25
Following pre-season abroad, van Nieff made his first appearance of the season in a thrilling 2-2 draw away against Mohun Bagan[10]. He scored his first goal of the season away against Jamshedpur FC with a curling long shot into the top corner. It was Mumbai's second goal of the match, but was not enough to prevent a 3-2 loss for the club[11].
He scored his second goal of the season away against FC Goa, picking up the ball near the centre circle, dribbling forward, and taking a long shot that went past FC Goa goalkeeper Laxmikant Kattimani and into the bottom corner[12]. This was Mumbai's first win of the season as well[13].