Chaves, who had declared for the Union, fought with his militia at the Union defeat at Valverde. Then at the Battle of Glorieta Pass, Canby and Major John Chivington chose Chaves to guide Chivington's force to the Confederate supply train.
Chaves, a Union supporter, participated in the battle at Valverde alongside his militia during the Union defeat. Later, at the Battle of Glorieta Pass, Canby and Major John Chivington entrusted Chaves with leading their forces to the Confederate supply train.