How did nationalism contribute to the unrest in the balkans in the late 1800?

It motivated ethnic groups to fight for territory.  

Explanation:

The Balkan peninsula, for centuries, ruled by the Ottoman Empire. By late 1800, the Ottoman Empire began to crumble and became restricted. During this period, Serbia, Montenegro, Greece, and Bulgaria all achieved independence from the Ottoman Empire. Nationalism was a dominant strength in these countries as a strong nationalism began to spring up among the people. In the Balkan region, many of the ethenic people long to fight for expanding their territories.                              

a big one is

to appoint and regulate officers of the land and naval forces,

which caused much controversy ending the articles