She and her husband lived in Liberia before emigrating to Canada, where she raised her young family while working as a sales manager selling Registered Education Savings Plans.

[citation needed] During her first term, she introduced a private members motion seeking to raise the age of consent.

[citation needed] From 15–18 May 2005, Grewal's husband surreptitiously taped his discussions with the Liberal Party which, he claimed, showed Liberal government officials enticing him to crossing the floor in exchange for patronage positions.

The Liberals were concerned with saving the government during the vote of confidence, and had also contacted MPs Chuck Cadman, Inky Mark, and Belinda Stronach (the last of whom did cross the floor, and was made a minister).

When the audio tapes were released, Nina Grewal publicly refused to comment about these discussions; the Liberals were cleared of any wrongdoing, and the Grewals had to explain in detail to the Parliamentary Ethics Commissioner about the discussions and secret tapings on 16 May.