Unfortunately it is not possible to translate the English texts in the Chosen JavaScript. Is it possible to update to Chosen version 0.9.3 (or higher)?
https://github.com/harvesthq/chosen/blob/master/chosen/chosen.jquery.js
And adjust line 1520 in form_display.php to:
return sprintf("jQuery('%s').chosen(%s)", implode(",", $chosen_fields), "{no_results_text:'" . __("No results match", "gravityforms") . "'}");
This way we can translate the "No results match" text for the Chosen JavaScripts.