Nicollet was born in Normandy, France, and he sailed to Canada in 1618 to work for a fur-trading company (the Compagnie des Marchands). He planned to live among the Native Americans, learn their language, negotiate, and trade furs.

From Quebec, Samuel de Champlain and Nicollet traveled up the St. Lawrence River and then the Ottawa River to an island in the Ottawa River (Alumette Island), where Nicollet remained for two years. During this time, Nicollet lived with the Huron and Algonquin tribes, learning their languages and customs.

In 1620, Nicollet returned to Quebec, but soon left to live among the Nipissing people (along the shores of Lake Nipissing, near Lake Huron).

Nicollet returned once again to Quebec in 1633. In 1634 he was sent to the Winnebago tribe to negotiate, and also to find a water route to Asia through southern Canada. He traveled up the Ottawa River to Lake Nipissing, down the French River to Lake Huron, and then across the lake to the straits of Michilimackinac, into Lake Michigan, and Green Bay (in what is now Wisconsin). Nicollet's route later became a major fur-trading route for the French. He also traveled along the Wisconsin and Illinois Rivers, possibly reaching the Mississippi in 1634.

Nicollet is known for wearing a brightly-colored, flowery, Chinese robe during his travels.