The strike also injured 113 people. Many of those killed and injured were women and children, said Emergency Lawyers, a rights group tracking violence in the country.
The group blamed the Sudanese military for the strike on the market, condemning the attack.
"This massacre transformed a civilian marketplace into a scene of mass killing and injury and is an assault that threatens the lives of residents and compounds their suffering amid the ongoing war," the group said in a statement.
It called for an independent investigation into the strike.
Doctors Without Borders, which is also known as Medecins Sans Frontieres, said earlier that 36 bodies arrived at its hospital in Nyala and reported seeing 150 injured in its emergency room.
Nyala, the capital of South Darfur province, is controlled by the paramilitary group Rapid Support Forces, which has been fighting with the Sudanese army since 2023.
Drone warfare has been a staple of this war but in recent weeks, a massive escalation of drone strikes by both the RSF and the Sudanese army has killed hundreds.
The conflict has created the world's largest humanitarian crisis, with about 34 million people - almost two out of every three Sudanese - needing assistance, according to the UN.
Sudan's war started in April 2023 when tensions between the military and the RSF exploded into open fighting in the capital, Khartoum, and spread across the country.
Separately, large parts of Khartoum were without electricity for more than 12 hours after a drone strike on a major power substation, according to an electric company official.
The attack left hospitals and bakeries dependent on generators and limited water supplies across the capital.
The state-run Sudanese Electricity Distribution Company acknowledged "serious damage and technical faults" to the distribution network and several main stations and power lines but didn't explain the reason in a statement.
The company apologised to residents across Khartoum state for repeated and prolonged outages.
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