In my own words I will like to say nationalism simply is a feeling that one's own country is better than others.
Over the years it has been known that countries with really high level of nationalism tends to dominate and even rule countries with low level of nationalism.
When the level of nationalism in a country is high,we notice that religions doesn't necessitates conflict, we see that at the call of nationalism,people tend to forget tribal differences, language problem etc
Nationalism by citizens of a country tends to reduce corruption. This can be explained in terms of when a citizen gets a political post, he is not after embezzling public funds for the betterment of his family but rather he will see to it that public funds are put into the right sectors in other to achieve growth of the country.
Now relating nationalism to my country Nigeria, I think I'm allowed to say that if citizens are nationalistic, we will see that the country will experience growth in many sectors in the sense that youths won't go about destroying government projects, killing fellow Nigerians. Also nationalism brings about participation in elections, qualified citizens go out to contest and also the masses goes out to vote.
Finally, I think the spirit of nationalism should be cultivated by every citizen in other to ensure growth in every sector of the country,from economic sector, social sector and political sector
NATIONALISM= ONENESS=GROWTH