@Mike-R Thanks for reaching out!
If your Chaco Sandals have a sole made with Vibram, you may be able to find a shoe repair shop in your area that can resole Vibram soles. You'll want to reach out to them to find out if they can do that kind of work. You can tell your Chacos have a Vibram sole by the yellow 'Vibram' symbol on the bottom of the sandal.
Otherwise, your best bet would be to go through Chaco itself to have your sandals resoled. You can find all their information about that process, including a phone number to call and chat with them, on their Chaco Sandal Resole site.
Hopefully this helps!