Liam Manning's side were the only lower-league club to knock out a Premier League side in the third round, as they got the better of West Ham United in a replay here.
Match preview
Tommy Conway was the hero for Bristol City, as it was his early strike in a replay last Tuesday that sealed their place in the fourth round.
It was also his goal at the London Stadium which forced the tie to a replay, and the Robins will now welcome another Premier League side to Ashton Gate.
That major scalp remains their only win in six games though, as they were held to a 1-1 draw by Watford at the weekend, meaning they have taken just two points from their last four league games.
Those results have seen Bristol City slip to 13th, six points adrift of the playoffs, but all focus will be on the FA Cup this weekend, as they look to replicate last season's achievement of making round five.
Manchester City got the better of them at that stage, meaning they have still not reached the quarter-finals since 1973, and with many Premier League sides left, it is unlikely they will win two more ties this season to change that.
Bristol City have never won the FA Cup in their history, as one cup final appearance 115 years ago remains their best-ever showing in the competition.
The two clubs have recent history considering they shared the same division for many years, and Forest got the better of Bristol City in both meetings during their promotion campaign in 2021-22.
That was under the since-departed Steve Cooper though, and even though results have been hit-and-miss under Nuno Espirito Santo, Forest have been incredibly entertaining to watch.
They have both scored and conceded in all six games under Nuno - scoring 14 and conceding 11 - and have taken a respectable six points in four league games.
A 3-2 weekend defeat to Brentford means they are just four points above the drop though, with a potential points deduction looming over them after breaching the Premier League's Profitability and Sustainability rules.
The drama has not stopped in their brief cup run so far either, as they needed a replay and extra time to get past League One Blackpool, but in doing so, exacted revenge on the Tangerines, who thrashed them 4-1 at Bloomfield Road at the same stage last season.
Their status as a Premier League club means Forest will hope to improve on a record that has seen them progress past round four just three times in the 21st century.
In their promotion campaign during 21-22, Forest also reached the quarter-finals of this competition, but it remains 33 years since they last reached the final, and 65 years since they last won it.
Bristol City FA Cup form:
D
W
Bristol City form (all competitions):
D
L
D
L
W
D
Nottingham Forest FA Cup form:
D
W
Nottingham Forest form (all competitions):
L
W
W
D
W
L
Team News
Scott Twine scored on his Bristol City debut last weekend, finding the equaliser which helped them to that 1-1 draw with Watford.
Twine's arrival coincided with Andreas Weimann's loan move to West Bromwich Albion, and the Burnley loanee should start again here.
On the treatment table are Ayman Benarous and Rob Atkinson, who are both recovering from ACL injuries, and Mark Sykes joins Kal Naismith on the sidelines with hamstring issues.
Forest were significantly weakened by the absences of Morgan Gibbs-White and Anthony Elanga in their defeat to Brentford last Saturday.
With Taiwo Awoniyi also out, the defeat has seemingly kicked Forest into life in the transfer market, as rumours have linked the club with moves for Giovanni Reyna and Carlos Borges this week.
Forest have more players away at the Africa Cup of Nations than any other Premier League side, and while Moussa Niakhate, Cheikhou Kouyate (both Senegal) and Ola Aina (Nigeria) have reached the knockouts, Ivorian trio Serge Aurier, Willy Boly and Ibrahim Sangare may return sooner.
Bristol City possible starting lineup:
O'Leary; Tanner, Vyner, Dickie; McCrorie, J Williams, James, Pring; Knight, Conway, Twine
Nottingham Forest possible starting lineup:
Vlachodimos; Montiel, Omobamidele, Murillo, Nuno Tavares; Dominguez, Mangala, Danilo, Yates, Hudson-Odoi; Wood
We say: Bristol City 1-1 Nottingham Forest
With Forest potentially lacking options in attacking areas, they may struggle to impose their superiority on Bristol City in an intriguing cup tie.