Gwede Mantashe remains the mineral resources and energy minister.
The Minerals Council South Africa welcomed Nkabane's appointment following the death in 2019 of her predecessor Bavelile Hlongwa.
"Following the violent events in KwaZulu-Natal and parts of Gauteng last month, the changed arrangements and personnel in the security cluster are timely," the council said of Ramaphosa's reshuffle.
"And we particularly look forward to developing a constructive working relationship with deputy minister Nkabane in the very near future," CEO Roger Baxter said.
Nkabane achieved a doctorate of administration from the University of KwaZulu-Natal in 2019, the same year she was elected to parliament.
KwaZulu-Natal, which was rocked by violent protests last month following the jailing of former South Africa president Jacob Zuma, was already a tinderbox due to issues including high unemployment and community discontent.
Continuing security concerns following the assassination of a mine manager on his way to work in May prompted Rio Tinto to halt its majority-owned Richards Bay Minerals operation in the province in June.
"The new members of president Ramaphosa's team enter office with very serious responsibilities given the country's deep economic, security and health crises," Baxter said.
