Who is known as nightengale of India?

Its Sarojini Naidu.

Here is a short biography of her:

Sarojini Naidu was born on February 13, 1879 at Hyderabad in a Bengali Hindu family. She was the eldest daughter of scientist, philosopher, and educator Aghornath Chattopadhyaya, and Barada Sundari Devi, a poetess. Sarojini was a very bright girl. At a very young age of 12, she topped the entire Presidency in Matriculation examination from Madras University. Due to her passion for reading, she took a break from studies and involved herself in extensive reading on various subjects. In 1895, at the age of sixteen, she traveled to England to study first at King's College London and subsequently at Girton College, Cambridge.