Why are there Philippine nurses in the US?

People from many different countries work as nurses, and in other professions, in the US. That is what Immigration is all about

• going to Another Country and making a living there.

In the case of the Philippines, the US controlled the country for some 50 years, and it was easier for a Filipino to travel to the US than for people from some other countries. That, combined with the fact that English is already an official language in the Philippines creates a tradition of moving to the US and makes the transition to the US somewhat easier, even though the Philippines is now an independent country.