The 25-year-old made 23 appearances across all competitions last season for Nuno Espirito Santo's side and was often employed as a substitute.
He scored three goals during his spell at Trentside, including a goal in his second game when he came off the bench on the left wing and notched an equaliser against Brighton in September.
Significant contributions in the third and fourth round of the FA Cup catalysed Forest's impressive run in the competition, but only claiming one goal in his league campaign reflected how Callum Hudson-Odoi ultimately left him in the shadows.
Nuno ultimately deployed the English winger in 36 matches as Forest could not afford to make the smallest of slips to grant teams around them the advantage.
The Paraguayan international has played quite a key role in his country's World Cup 2026 qualifying campaign, but his most recent omission from the starting lineups against Uruguay and Brazil highlighted his status as an outcast for The Tricky Trees.
Sosa arrived at The City Ground from the Argentinian side Talleres for a similar price tag to his latest sale price.
He will cross to the neighbouring rival country Brazil for the first time in his career as Palmeiras look to bolster their attacking options.
Sosa has signed a five-year contract, and Estêvão's transfer to Chelsea also would have prompted them to sign a replacement.
Rather than a regression back to South American football, it gives Sosa an opportunity to gain experience and playing time.
His days at Nottingham Forest are numbered for now, but he may still be able to make a return to European football if his career accelerates enough for club and country, with next year's World Cup potentially being an opportunity to showcase his talent on the wing.
Palmeiras are currently fourth in the Brazilian top flight, which runs from March to December each season, and were recently knocked out by Chelsea in the quarter-finals of the ClubWorld Cup.
Nevertheless, they have garnered their fair share of the prize pool from their impressive showing in the United States.
As Anthony Elanga's move to Newcastle United for a reported £55 million is looming, Forest and their newly-appointed Global Head of Football, Edu Gaspar, need to act swiftly to add players to their attacking department.
With the Premier League opening day almost a month away and pre-season already getting underway, Nuno Espirito Santo will surely be pushing for new recruits as he looks to implement his tactical plans and match them with suitable personnel.
Jota Silva only started in five games in his 31 Premier League appearances last season, and adopted a similar position in Forest's ranks to the outgoing Sosa.
Callum Hudson-Odoi scored just five goals compared to his tally of eight in 23/24, however, his consistent threat in transition, which mirrored the traits of Elanga, proved superior to anything Sosa or Silva had to offer.
A player that aligns with the profile of Hudson-Odoi or Elanga will not be readily available in the market for Forest to pounce upon, but pursuing a target who demonstrates similar attributes to the two star wingers from last season would perhaps be an apt approach to take.