<?php

use DrupalComponentUtilityHtml;
use DrupalnodeEntityNode;

function _update_node() {

// load nodes
foreach($nids as $nid) {
    $node = Node::load($nid);

// do the work  here

  $node->save();

}

drush eval "module_load_include('inc', 'create_content', 'create_content'); _update_node();" > debug.txt

$node = Node::load($nid);
$node->set('body', [
  'summary' => 'the summary',
  'value' => '<p>something</p>',
  'format' => 'full_html', // probably
]);
$node->save();