Wells won gold at the event, pushing last year's champion and recent Winter X-Games gold medallist, Frenchman Charles Gagnier, into second place.
Wells' prize cheque equates to $NZ11,503, and comes a month after he became the youngest person (at 17) to win a medal at Winter X-Games in Aspen, where he came second behind Gagnier.
The pair have continued a rivalry, which began in New Zealand last year when Gagnier secured wins in the national Freeski Championships at Wanaka's Snow Park, to the northern hemisphere circuit.
New Zealand snowsports website www.snow.co.nz said Wells was now in the position of earning more medals than any other athlete on the competition circuit.
His are the most consistent top-level snowsports results a New Zealand freestyle skier has ever achieved.
Lyndon Sheehan, also of Wanaka, was fourth at the Nippon Open.