Nigeria is a Muslim country or not?

NIGERIAN FLAG

The flag of Nigeria was designed in 1959 by Taiwo Akinkunmi.

first officially hoisted on 1 October 1960. The flag is a vertical 1:2 triband of green, white, green. The two green stripes represent Nigeria's natural wealth, while the white band represents peace.

Any country that didn't fight to get independent always use green and white or blue and white...

Green and white is symbolic color in Islamic world and has meaning to Islamic believer.

Today people are protesting to return the Arabic inscription on the naira note...

WHY IS GREEN IS SO PREVALENT IN THE ISLAMIC WORLD?

Because it was supposedly Mohammed's favorite color. The Islamic prophet is said to have worn a green cloak and turban

Reclining on green Cushions and rich Carpets of beauty
—  Sura 55, verse 76. [1]
Upon them will be green garments of fine silk and heavy brocade, and they will be adorned with bracelets of silver; and their Lord will give to them to drink of a Water Pure and Holy.
—  Sura 76, verse 21. [2]
[3]

A passage from the Quran describes paradise as a place where people "will wear green garments of fine silk." One hadith, or teaching, says, "When Allah's Apostle died, he was covered with a Hibra Burd," which is a green square garment. As a result, you'll see green used to color the binding of Qurans, the domes of mosques,

During the crusades, Islamic soldiers wore green to identify themselves..

White is perhaps the second-most associated color with Islam. The color white symbolizes purity and peace and so it is often worn by Muslims attending Friday prayers.

Green white green is it a sign that Nigeria is an Islamic republic and that is why that Nigeria Muslims always claim that the country belong to them..