Wallace was born in 1994 in Berwick, Victoria. Her family moved to the Coffs Harbour region of NSW and she was first introduced to AFL at the Sawtell Toormina Saints club under coach Tony Linnett. She was playing for Coolangatta Tweed Heads when she was drafted.[1]
Wallace was delisted by Brisbane at the end of the 2017 season.
After spending 2018 to 2020 at VFLW club Williamstown Wallace played for Waratah NTFL club for part of season 2020/2021. Wallace continued her VFLW career in 2021 at the North Melbourne Football Club, and was named the captain.[4][5]
The Best and Fairest Medal for the AFL North Coast Youth Girls age group is named the Nikki Wallace medal in recognition of Nikki being the first player from the region to play AFLW.