Nelson (37), who works in the office for Alexandra-based shearing contractors Peter and Elsie Lyon, beat two world champions to take the title.
She has not done much wool-handling lately and has not won an event since her third New Zealand merino championships victory in Alexandra more than two years ago.
She faced tough opposition in the final, including from 2010 world teams champion Keryn Herbert, of Te Awamutu, and two-time world teams champion Tina Rimene, formerly based in Alexandra and Masterton and now employed as upper South Island chief wool-handling instructor for industry trainer Tectra.
The last of the three to finish and conceding almost 10 points to Herbert, the 2010 event winner, Nelson's wool points were far superior and gave her a comfortable victory with 273.25 points.
Herbert was second with 302.97 points and Rimene third with 306.42 points.
Anne-Maree Kahukura, of Omakau, was second in the senior final, while Sheree Peterson, from Milton, was third.