Human rights is a nation wide problem, and every larger and more affluent nation should be working together to make sure that other nations have the same rights as they do. Countries that have more human rights should be fighting for those people in other countries that don't have basic human rights that they deserve.
World leaders should definitely focus on human rights issues world over. Every part of the world is affected by problems of varying natures. Human rights violations in Nigeria too needs to and must be urgently addressed. To begin with Nigerian leaders must themselves start to do more to address the issue.
The UN was designed to create an umbrella around the world in attempts to curtail another Adolf Hitler and his goons from causing the same horrific hardships that they had done during WWII. It was also created to stall any chance of another world war. The UN created a WHO to monitor diseases and they developed a legal system to bring bad guys to justice. Yes, they should pay attention to the Nigerian people and their plights.
It's not right to divide people according to their race, color or nationality. Of course, world leaders have to pay attention and help to protect human rights all over the world, not only in Nigeria. Being leader of powerful country means take care of people, who live in less developed country.