The word for nshima changes with the region: what's ubwali in Bemba-speaking Kasama is nsima in Chewa areas and takes other names again along the Zambezi.
In Bemba-speaking Northern Province, the staple porridge Zambians elsewhere call nshima is traditionally pounded from finger millet flour and known as ubwali — denser, darker and earthier than the maize version. It's still cooked this way in and around Kasama.