The effort was the 30-year-old s second goal in the French top-flight this season after 13 matches.
The Tunisia international was in action for 82 minutes alongside Gabon s Denis Bouanga, Guinea s Saidou Sow, Algeria s Ryad Boudebouz and Senegal s Pape Cisse, who were on parade for Saint-Etienne.
Angers, on the other hand, had a host of African stars on parade including Morocco s Sofiane Boufal, Cameroon s Stephane Bahoken, Guinea s Lassana Coulibaly and Ivory Coast trio of Souleyman Doumbia, Ismael Traore and Abdoulaye Bamba.
Saturday s result moved Saint-Etienne to 16th in Ligue 1 with 33 points after 29 matches – eight points adrift of the drop zone.
Khazri will be expected to build on his match-winning goal when the Greens host Monaco for their next outing on March 19.
Tunisia captain Khazri powers Saint-Etienne to victory on his return from injury
goal.com - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from goal.com Daily Mail and Mail on Sunday newspapers.
Tunisia captain Khazri powers Saint-Etienne to victory on his return from injury
goal.com - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from goal.com Daily Mail and Mail on Sunday newspapers.
The goal extended the 25-year-old s tally to three goals after 20 Ligue 1 matches this season.
It did not take long for Nantes to double their lead as Imran Louza found the back of the net from the penalty spot in the seventh minute.
Despite their slow start to the game, Angers were handed a chance to reduce the deficit towards the end of the first-half after Ivory Coast s Souleyman Doumbia was brought down in the penalty area.
Morocco s Sofiane Boufal immediately stepped forward but his effort was saved by goalkeeper Alban Lafont. Fortunately for the hosts, VAR ordered a retake of the kick because Lafont was not positioned well on his goal line.
PSG stars prepare for Montpellier without new boss Pochettino
By Paul Myers - RFI
FRANCK FIFE AFP/Archives
Paris Saint-Germain boss Mauricio Pochettino will miss Friday night s game against Montpellier as he continues his recovery from the coronavirus.
The 48-year-old Argentine contracted the disease last week just before PSG s match at Angers.
Assistant coach Jesus Perez took charge of the side for the game at the Stade Raymond Kopa and oversaw a 1-0 win which allowed them to go top of Ligue 1.
Perez said Pochettino was making steady progress. Every person who is suffering or has suffered the virus needs to be worried.