Nandy was born to Mary Charles, a tailor and Charles Mfinanga, a mechanic. The name Nandy is shortened from her traditional name ' Nandera ' She started performing at a very young age. At 5 years of age, she was an active member of her Sunday school choir at KKKT Lutheran church in Moshi. She attended Mawenzi Primary School and later joined Lomwe High School where she became the head of the School choir. After high school, she joined the College of Business Education (CBE), Dar es Salaam, Tanzania.
Her music career kicked off when a mutual friend introduced her to Ruge Mutahaba, CEO of Tanzania House of Talent (THT). There, she met Emma the Boy, who produced her first mainstream single, Nagusagusa. The song became a huge hit within a week of its release.
In early 2016, she participated in a singing competition, Tecno Own the Stage, which featured contestants from across Africa. During the finals in Lagos, Nigeria, Nandy emerged as the first runner-up. The competition groomed her musically, helping her gain performance confidence and acquire essential knowledge of the music industry from musical tutors and mentors such as Chocolate City's M.I Abaga, Yemi Alade , and Bien of Sauti Sol.
In 2017, she released her hit single One Day which spearheaded her career and gave her a couple of opportunities. That year, she was one of the few artists who participated in Coke Studio Africa and was later nominated at the All Africa Music Awards as Best Female Eastern Africa.Nandy is also a successful entrepreneur with her own beauty and fashion company, and serves as Tanzania's Goodwill Ambassador for UNICEF's water, sanitation, and hygiene program.