Answer:
Nationalism is a hard topic to decide if it is good or bad, although it can bring about dictators like Hitler and Napoleon, Nationalism does have it's good traits.
For example; In sports a whole nation can be brought together to cheer for their country's team. People who would normally be competitors join forces to cheer for one cause. This is like in any competition, but the main focus is that it can be used as a tool to bring people together.
This also creates pride in one's country, fueling confidence. When one goes travelling to a forgien land why do they put a Canadian, or American flag on their rucksack? Because their proud to display that their part of that country. In this way, nationalism influences confidence. Also, I'm sure as many others have, when travelling to another country, if one happens to encounter another citizen of your country in that forgien place you and that parson feel immediatley bonded. This is also another positive occurance.
Nationalism also makes the wellbeing of one's nation important and aids in economic advances.