Not quite true, can't pin this on Southern Nigeria or the government because for most of Nigerias history even under colonialism the North was in power and it is the Northern elites who left their native lands underdeveloped in order to maintain their position.
Ok lets say "ethnic/ tribal politics"
Either way, until they develop Northern Nigeria, there will always be violence. Defeat Boko Haram but leave it poor and a new group will form. People get frustrated when there is no jobs and they lack education so it is easy to be misguided into radical religion.