Nel's clinical performance was supported by further tries from Neels Volschenk and CJ Coetzee, as the Cheetahs secured a comfortable bonus-point win. Flyhalf Tiaan Swanepoel converted five of their six tries, with Cohen Jasper adding the final conversion after Swanepoel left the field.
The Pumas, who had been unbeaten in all competitions this year until now, crossed for four tries through Ross Braude (2), Sango Zamlashe, and Wian van Niekerk. However, poor goal-kicking cost them, with flyhalf Danrich Visagie missing three conversions and slotting only a single penalty and one conversion.
The visitors struck first when Braude dotted down from a maul break, but the Cheetahs responded immediately as Nel stepped through to score under the posts. Nel then intercepted a loose pass to race 70m for his second try.
The Cheetahs stretched their lead before halftime, with Nel completing his hat-trick from close range and Volschenk powering over after a dominant scrum. The hosts led 28-13 at the break.
CJ Coetzee added a spectacular solo try early in the second half, evading four defenders to score. Despite Braude and Zamlashe crossing for the Pumas, their missed conversions left them chasing the game.
Nel sealed the win with his fourth try in the dying moments after the Cheetahs won a turnover from the restart, capping a dominant display.