Nienaber won several amateur events in Africa and represented South Africa at the 2018Eisenhower Trophy in Ireland, where he finished 3 under par individually.[1] He made his European Tour debut as an amateur in December 2018 at the South African Open at Randpark Golf Club, north of Johannesburg, where he opened with two rounds of 69 to make the cut.[2]
Nienaber turned professional in the middle of 2019. His European Tour debut as a professional was made in late November 2019 at the Alfred Dunhill Championship at Leopard Creek CC, Malelane, South Africa, where he finished tied 24th, earning €14,000.
In February 2020, also in his homeland of South Africa, he came close to his first professional win, finishing runner-up in the Limpopo Championship on the Challenge Tour.
In September 2020, 14 months after turning professional, Nienaber advanced to 270th on the Official World Golf Ranking.[2] In the second round of the Joburg Open in November 2020 at Randpark Golf Club in Johannesburg, South Africa, Nienaber hit his drive on the 597-yard, par-5 4th hole a European Tour season record 439 yards. It was also 16 yards longer than the PGA Tour season record at the time.[5] He eventually finished in second place; two shots behind Joachim B. Hansen, and reached a career best 209th on the Official World Golf Ranking.
In May 2021, Nienaber claimed his first professional victory at the Dimension Data Pro-Am. He beat Henric Sturehed in a playoff[6] and advanced to 135th on the Official World Golf Ranking.
Amateur wins
2017 Northern Cape Amateur Open, Central Gauteng Open Stroke Play
2018 Free State Open, Western Province Amateur Strokeplay
