Conversation so far:
In what city did the Chimu expand their territory?
The Chimu territory developed in the Moche Valley north of present-day Lima and later expanded to Arequipa. To the south, they expanded as far as Carabayallo.
What sort of terrain did the Chimu live on?
The Chimú resided on a strip of desert on the northern coast of Peru. The rivers in the region carved a series of fertile valley plains well-suited to irrigation.
Was it difficult for the Chimu to find food?
The Chimú developed excellent agricultural techniques which expanded the strength of their cultivated areas. They cultivated beans, sweet potato, papaya, and cotton with their reservoir and irrigation system.

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