Nunez is expected to be at the centre of a transfer tussle between several of Europe's top clubs after ending the 2021-22 season with 34 goals in 41 matches across all competitions.
The Uruguay international comfortably scooped the Primeira Liga Golden Boot with 26 goals in 28 league matches, putting him six clear of closest challenger Mehdi Taremi.
Nunez also found the back of the net six times in the Champions League for Benfica, who are seemingly resigned to losing the 22-year-old in the summer transfer window.
Liverpool, Newcastle United and Real Madrid have all been linked with a swoop for Nunez, whose contract with Benfica does not expire until the end of the 2024-25 season.
However, a recent report claimed that Man United are edging closer to winning the race for the striker's signature, but the 20-time English champions are still hopeful of driving the price down.
According to The Independent, Benfica will demand a fee of £100m in straight cash to part ways with Nunez, leading United to offer Pereira in a player-plus-cash deal.
The report adds that Benfica are aware of United's pursuit of Nunez, but the South American has earmarked Liverpool as his preferred destination following United's failure to qualify for the Champions League.
Twenty-six-year-old Pereira returned to his native Brazil with Flamengo for the 2021-22 season after falling out of favour at Old Trafford and is widely expected to leave the Red Devils permanently this summer.
Pereira has featured regularly for Flamengo during the start of the 2022 Serie A season, although there are fears that the Brazilian side may not be in a position to take up their option to buy the midfielder.
As a result, there have been suggestions that Erik ten Hag could offer Pereira the chance to resurrect his Red Devils career, with the midfielder scoring four goals and providing five assists in 75 games for the club so far.
Man United are set for a summer shake-up in all areas of the pitch under Ten Hag, but Cristiano Ronaldo has seemingly confirmed his desire to remain at the club for the 2022-23 season.
Marcus Rashford could also be handed a lifeline after his troubled 2021-22 campaign, but Anthony Martial is expected to complete a permanent switch elsewhere.
Paul Pogba, Juan Mata, Edinson Cavani, Jesse Lingard, Nemanja Matic and Lee Grant have already left the club as free agents, and a mass exodus of defenders could see Eric Bailly, Phil Jones and Axel Tuanzebe also head elsewhere.
As well as Nunez, Man United are also said to be closing in on the signing of Barcelona's Frenkie de Jong after a breakthrough in negotiations with the Catalan giants.