Ashirvad's answer no longer works. Note the class name changes and using the option element instead of the li element. I've updated my answer to not use the deprecated "success" event, instead opting for .done():
$('.chosen-search input').autocomplete({
minLength: 3,
source: function( request, response ) {
$.ajax({
url: "/some/autocomplete/url/"+request.term,
dataType: "json",
beforeSend: function(){ $('ul.chosen-results').empty(); $("#CHOSEN_INPUT_FIELDID").empty(); }
}).done(function( data ) {
response( $.map( data, function( item ) {
$('#CHOSEN_INPUT_FIELDID').append('<option value="blah">' + item.name + '</option>');
}));
$("#CHOSEN_INPUT_FIELDID").trigger("chosen:updated");
});
}
});