The 24-year-old has emerged as a potential target for Oliver Glasner, with Forest expected to consider further additions when the winter transfer window opens.
Brown is under contract with Fenerbahce until 2028, but reports in Turkey claim Forest are preparing an offer for the former Derby County youngster.
Fenerbahce are reluctant to lose Brown midway through the season and would reportedly demand at least €30 million (£25m) if the defender indicates that he wants to leave.
That figure is roughly twice the €15m (£12.6m) Forest are said to be prepared to pay, meaning negotiations would be required if the Premier League club formalise their interest.
Brown was also linked with Sunderland and Atletico Madrid before the summer window. Sunderland were reportedly prepared to offer €16m (£14m), but the left-back ultimately remained in Turkey.
The Englishman came through the youth systems at West Bromwich Albion and Derby County before moving to Switzerland with Lausanne-Sport.
He later joined Belgian club Gent before signing for Fenerbahce in the summer of 2025.
Brown has made 10 appearances across league and European competition this season, scoring twice.
Nottingham Forest’s interest comes after Glasner opted against further additions towards the end of the summer window, having decided there was insufficient time to complete the necessary due diligence on potential targets.
Neco Williams has been the first-choice left wing-back so far, while Luca Netz provides another option on the left. However, Netz has largely been restricted to a substitute role since joining the club in February.
Cuiabano is another option for Forest but is currently on loan at Vasco da Gama, with his temporary spell due to end in December. Vasco have an option to make that move permanent.
Forest’s reported interest in Brown therefore gives Glasner another potential solution on the left, although the gap between the two clubs’ reported valuations could prove the main obstacle to a January deal.