On 1 July 2015, Nicolas signed with Borussia Mönchengladbach, where he made his debut for the reserve team in the Regionalliga West on 31 October 2015 in a 3–1 home defeat to Viktoria Köln.[7][8] During summer training camp in 2016, Nicolas was included in the first team's pre-season preparations, while still being a part of the reserves as well as Mönchengladbach's under-19 side.[5] At the end of the 2018–19 campaign, he had made 75 appearances for the reserves in the Regionalliga West.[9]
Union Berlin (loan)
Nicolas joined Bundesliga club Union Berlin on a two-year loan deal on 31 May 2019.[6] He made his professional debut for Union in the Bundesliga on 20 June 2020, starting in the 4–0 away loss to 1899 Hoffenheim.[10][11] His loan was cut short on 15 August 2020 after making only one appearance for the Berlin side.[12]
VfL Osnabrück (loan)
The same day, Nicolas joined 2. Bundesliga club VfL Osnabrück on a season-long loan.[13] On 28 February 2021, he made his debut for the club, starting in place of the benched Philipp Kühn in a 3–0 league loss to SV Sandhausen.[14] After the game, Nicolas was demoted to backup again, and he would only go on to make the one appearance for Osnabrück before his loan expired.[15][16]
Viktoria Köln (loan)
On 15 July 2021, he moved to 3. Liga club FC Viktoria Köln on loan.[17] He made his debut on the first matchday of the 2021–22 campaign, in a 2–1 loss to recently promoted Viktoria Berlin.[18] He remained a starter throughout the season, making 34 total appearances for Viktoria as they suffered relegation to the Regionalliga at the end of the campaign.[9]
Roda JC (loan)
On 17 August 2022, Nicolas joined Eerste Divisie club Roda JC on a season-long loan.[19] He made his debut on 5 September 2022, starting in a 1–1 draw in the derby against MVV.[20] He remained the starter in goal afterwards in place of Rody de Boer,[21] returning to Mönchengladbach at the end of the season with 30 league appearances for Roda.[16]