I have followed the instructions on the project page: extracted the .js and related files to /sites/all/libraries/chosen/chosen/; I downloaded, installed, and enabled the module without incident. I have checked to make sure that the "chosen" library files have the correct permissions on the server, and that I have the "administer site configuraion" permission.
The configuration page at configuration>>user interface>>chose only has two fields; "minimum number of options" and "apply chosen to the following elements".
When I go to my taxonomy term reference fields which have "select" widgets, I go into the field settings (as instructed on the drupal.org project page), and there is no option to "apply chosen to this field".
This module looks like it would be very useful: is there a way to get it working on taxonomy term reference "select list" widgets?