by MARIA BRADSHAW THREE NIGERIAN CHILDREN are now in the custody of the Child Care Board. It is understood that their mother, a Nigerian nurse who was attached to the Queen Elizabeth Hospital, took them there last Friday and told authorities that she could no longer care for them. Director of the board, Joan Crawford, confirmed that the children were in their care but would give no additional information. But reliable sources told the DAILY NATION that the woman was supposed to leave ...