The 42-year-old manager of a community support centre said the lump was not the "pea type" tumour she had imagined.
Even her GP and surgeon didn't think she had anything to worry about, but a series of tests proved otherwise.
It was not long before a 2.1cm cancerous tumour and eight lymph nodes from under her arm were removed by surgery and Ms Smith embarked on a six-month course of chemotherapy, followed by a six-month course of radiotherapy.
Speaking before Daffodil Day, being marked across New Zealand today, she paid tribute to the New Zealand Cancer Society for providing advice, practical help and friendship.
"They're absolutely fantastic.
"I didn't expect to feel so supported and it made such a huge difference to me and my family."
Staff and volunteers did many things to help her along the way, from delivering baking, enrolling her in a "Look Good, Feel Better" course and introducing her to other survivors.
"That was the biggest thing.
"When I got cancer, I wanted to be around other people who knew what I was going through.
"The companionship was very important to me."
In Dunedin for six weeks, Ms Smith stayed at the Cancer Society's residential facility, Kowhai House, which was like "being on holiday".
She split her time between treatments, swimming and crocheting - a hobby she had as a child and has taken up again since her diagnosis.
Since being told she had cancer, Nicki has made about 80 beanies, most of which have been given to the Cancer Society.
After months of treatment she is now confident she has beaten cancer and is making more time for herself - and the horse she has leased, called Lochie.
She had not owned a horse since her teens and Lochie was helping her heal, she said.
"I think horses are very therapeutic - just lovely animals that seem to be sensitive to how you're feeling."
