Question

Why do you think European nations supported the colonists rather than great britain

Answer 1

A lot of European nations, such as France, were actually enemies of Great Britain, as many of the countries in Europe fought against each other for power, land and resources. So they would support the colonists, just because it would weaken Great Britain.

Answer 2

The French and Indian War had drastically changed the balance of power in North America. The French and Spanish had lost a large expanse of valuable land to the British. The European Nations decided to help the colonists because they (the Europeans) were enemies themselves of the British.After the Seven Years War and French and Indian War, Britain became the major power in Europe. Spain and French, the two European nations that aided the colonies during the American War of Independence, had a lot to gain if Britain lost. 
Not that much happened. While the French helped the Colonies fight on land, the British soundly defeated any attempts to take the West Indies, which were of higher importance.Some European nations such as France and Spain supported the colonists because they thought once they got Great Britain out of the picture than they could take control of the colonists.To cut Britain down to size. They certainly had no reason to support Britain, which was keeping them out of its colonial trade. Empire is a cut-throat business, and the last thing you want is someone else having one.The foreign nations that supported the colonists were either at war with the British, or were afraid of Britain declaring war on them. France took a big chance when they supported the colonists.