Though I didn't look at the nursing situation in particular, I wrote a paper on medical migration from low and middle-income countries and addressed steps to improving motivation and retention of health professionals.
The paper is a systematic review. Here's the link:
Summary: This paper examines various aspects of the nursing and midwifery workforce in Africa, looking at education and supply systems; recruitment, retention and motivation and career systems. It further investigates attrition from migration and HIV/AIDS, as well as other factors and makes some recommendations on how to move forward
using examples of experiences from countries.
Source: International Council of Nurses - ICN