The Paraguay forward, a summer signing from Argentinian club Talleres, capitalised on a defensive lapse from the Seagulls with 20 minutes remaining at the Amex Stadium.
Quick-fire goals from Jack Hinshelwood and Danny Welbeck at the end of the first half turned the contest in Albion’s favour following an early penalty from Chris Wood.
Forest finished the match with 10 men after captain Morgan Gibbs-White was shown a second yellow card in the 83rd minute for a lunging challenge on Joao Pedro, with Forest boss Nuno Espirito Santo and Brighton head coach Fabian Hurzeler also dismissed.
A battling draw for the away side came two days after the 20th anniversary of the death of the club’s most successful manager, Brian Clough.
Both sides end the day with nine points from five top-flight games.
Brighton handed first league starts of the season to Pervis Estupinan and Simon Adingra, while Forest recalled Callum Hudson-Odoi and Anthony Elanga following their impressive impacts from the bench during last weekend’s 1-0 win away to Liverpool.
Hudson-Odoi, who claimed the winner at Anfield, made another telling contribution as the visitors snatched a 13th-minute lead.
After Gibbs-White powered down the right, the former Chelsea winger was bundled over in the box by Carlos Baleba, allowing one-time Brighton loanee Wood to slam the resultant spot-kick into the bottom left corner.
Albion dominated first-half possession but struggled to create for large parts, with the growing frustration of home fans increased by a series of fussy decisions from referee Robert Jones.
Yet the mood on the terraces improved significantly during a major momentum shift in the closing minutes of the half.
Hinshelwood levelled in the 42nd minute, powerfully heading home after Jan Paul van Hecke’s cross from the right flicked off Gibbs-White.
Albion completed a rapid turnaround just three minutes later.
Kaoru Mitoma’s promising dribble was illegally halted by Ola Aina and Welbeck curled the subsequent free-kick into the bottom right corner beyond the static Matz Sels in front of a stunned away end.
The goals came from the Seagulls’ first attempts on target.
Nuno responded by making a triple change for the second period as Neco Williams, Ryan Yates and Jota Silva replaced Alex Moreno, James Ward-Prowse and Elanga.
Welbeck looked certain to double Brighton’s lead within five minutes of the restart but visiting goalkeeper Sels, who was criticised for being beaten by the free-kick, made partial amends by producing a crucial save with his foot.
Brighton’s hard work was undone in the 70th minute as Forest levelled.
Gibbs-White exploited a gaping hole in the hosts’ backline after Albion centre-back Van Hecke was attracted to the ball and Jota raced clear to square across goal and gift fellow replacement Sosa a simple tap-in.
Having been instrumental in the equaliser, Gibbs-White, who was earlier booked for pulling down Georginio Rutter, then departed prematurely after halting Pedro’s attempted breakaway.
Nuno was incensed by the decision and he and counterpart Hurzeler also trudged down the tunnel after each being red carded.
Brighton were given six minutes of additional time to make their numerical advantage count before being forced to settled for a third successive top-flight draw.