Priyanka was born in the Bengali-speaking Kothari family in Calcutta, West Bengal, India. Her dad is a chemical businessman, mom is a home-maker, and she has an elder sister who is married. As a child she grew up in Calcutta, but most of her teen years were spent in Delhi where the family re-located subsequently. She is a Science Graduate from Dayal Singh College, which is an affiliate of Delhi University. She comes from a very conservative background but had always wanted to become an actress. She speaks English, Bengali, Hindi, and even a little bit of Rajasthani.

She modeled initially in Mumbai, and when actor Madhavan came there for a Pepsi commercial shoot, she met with him, showed him her photographs, he arranged an audition for her in Chennai, and she was signed for a Tamil movie titled 'Jay Jay' during the year 2003. She then also appeared in a Telugu movie 'Madhyanam Hatya' during 2004. In both the Tamil and Telugu movies she had a screen name of Amoha. She has also modeled with Indian Cricketer Kapil Dev.

This exposure got Bollywood movie-maker Ram Gopal Varma to approach her and sign her up in 'James' 'Sarkar' and subsequently in the Sholay re-make 'Ram Gopal Varma Ki Aag' in which she plays Ghunghroo, which was originally played by Hema Malini with a character name of Basanti. Her screen name is Nisha Kothari for all of the Bollywood movies.