umukōbwanyu (aba-  1  class 1
singular: umu-
plural: aba-
1. daughter of your sister (if the one spoken to is a girl), 2. daughter of your brother (if the one spoken to is a boy)
daughter    umukōbwa
(of my, your, his sister if one is girlof my, your, his brother if one is boy) umukōbwācu, umukōbwānyu, umukōbwābo
En-En dictionary 
niece    (daughter of sister, if a girl; daughter of brother, if boy) umukōbwacu, umukōbwanyu, umukōbwabo
(daughter of brother, if one is a girl) umusēngezana
(daughter of one's sister if one is a boy) umwīshwa
En-En dictionary