Who were the first European settlers in India?

The Portuguese.

"The colonial era in India began in 1502, when the Portuguese established the first European trading centre at Kollam, Kerala. In 1510 the Portuguese sailor, Vasco da Gama, established an important trading presence in Goa."
https://en.wikipedia.org/wiki/European_colonies_in_India

"Kollam is a city and a municipal corporation in Kollam district in the Indian state of Kerala....The Portuguese were the first Europeans to establish a trading center at Kollam in 1502. In 1661 the Dutch took possession of the town."
https://en.wikipedia.org/wiki/Kollam

The first Portuguese encounter with India was on May 20, 1498 when Vasco da Gama landed in Calicut (Kozhikode) in the present-day Indian state of Kerala.

https://en.wikipedia.org/wiki/Portuguese_India

https://exploration.marinersmuseum.org/subject/vasco-da-gama/

The first European to land on the shores of India was a Portugeuse sailor by the name of Vasco da Gama who, after sailing around Cape of Good Hope, landed on the Port of Calicut on the Malabar Coast of India in 1498.

If we are taliking about the first Europeans to get to India, then it may be Alexander the Great, who conquered part of Northern India (now Pakistan) in 327 B.C.

http://www.sparknotes.com/biography/alexander/section11.rhtml

He also had a policy of assimilation, whereby his soldiers would marry local women.