Try this:
function post_type_categories() {
$field_args = array(
'labels' => array(
'name' => 'Categories', 'taxonomy general name',
'singular_name' => 'Category', 'taxonomy singular name',
'search_items' => 'Search categories',
'all_items' => 'All categories',
'parent_item' => 'Parent category',
'parent_item_colon' => 'Parent category:',
'edit_item' => 'Edit category',
'update_item' => 'Edit category',
'add_new_item' => 'Add new category',
'new_item_name' => 'New category',
'menu_name' => 'Categories',
),
'hierarchical' => true
);
register_taxonomy( 'post_type_categories', '{your_post_type_name}', $field_args );
}