Nelson, a Paralympic Games and world championship medallist, posted victories in the 200-metre individual medley, 50 butterfly and 50 freestyle in the S7 disability category.
''There are a lot of talented up and comers and I want to make sure I'm on track to reach my goals for next year,'' said Nelson, 22. ''I absolutely want to go to the world championships and the Parapan American Games. Tonight I was most happy with 200 IM, especially the butterfly leg.''
Meanwhile Adam Purdy of London, Ont., who ended an eight-year retirement in 2014, won the men's S6 50 butterfly.
''It's been fantastic to be back competing again,'' said the 33-year-old Purdy, who won silver in the 50 backstroke at the Para Pan Pacific Championships in August. ''I'm getting a lot of energy from the younger kids, plus I'm capitalizing on my experience. I just feel like I'm a more aware athlete than I use to be.''