Conversation so far:
What city did the Chimu expand their territory in?
conquering the head of the valley of Chimor and the neighboring valleys of Sana, Pacasmayo, Chicama, Viru, Chao and Santa..
What sort of terrain did the Chimu live on?
At its peak, the Chimu advanced to the limits of the desert coast to the valley.
Was it difficult for them to find food?
CANNOTANSWER.

Question: Did they have to use force in order to expand?
Self-contained rewrite: Did Chimu have to use force in order to expand?