created_at_NT.php

add_filter('ninja_tables_item_attributes', function ($attributes) {
    $values = json_decode($attributes['value'], true);

    if(isset($values['created_at']) && !$values['created_at']) {
        $values['created_at'] = date('Y-m-d h:i A', current_time('timestamp'));
        $attributes['value'] = json_encode($values, JSON_UNESCAPED_UNICODE);
    }

    if(isset($values['updated_at'])) {
        $values['updated_at'] = date('Y-m-d h:i A', current_time('timestamp'));
        $attributes['value'] = json_encode($values, JSON_UNESCAPED_UNICODE);
    }

    return $attributes;
});