How to alter field values on a display page?
If I need to manipulate the text and/or display based on some PHP logic, I would do it using hook_node_view() in a custom module, not in a template file.

function MYMODULE_node_view($node, $view_mode = 'full', $langcode = NULL) {
    if( $view_mode == 'full' ){
        if( some conditions here ){
            $node-&gt;content['field_title_nickname'] = array(
                '#markup' =&gt; '&lt;div&gt;A new nickname title 2x&lt;/div&gt;'
            );
        }
    }
}