Help upgrading deprecated getTemplateVarOutput method from 2.0.x to 2.2.x

<?php
/* @var $modx modX */
  
$c = array(
    'hidemenu' => 0,
    'published' => 1,
);

$p = array(
    'placholdername' => 'value',
);

$output = '';
$children = $modx->resource->getMany('Children', $c);
  
foreach($children as $child) {
    /* @var $child modResource */
    $fields = $child->toArray();
    $fields['imgSource'] = $child->getTVValue('ProductImage');
    $output .= $modx->getChunk('ThreeImgChunk', $p);
}
return $output;

if (empty($chldren)) {

    echo "\nNO Chilodren\n";
}

echo "\nIMAGE SOURCE: " . $fields['imgSource'];

echo "\nFIELDS: " . var_dump($fields) . "\n";

$c = $modx->newQuery('modResource');
$c->where(array(
    'hidemenu' => 0,
    'published' => 1,
));

$sortBy = isset($scriptProperties['sortBy'])? $scriptProperties['sortBy'] : 'menuindex';
$sortDir = isset($scriptProperties['sortDir'])? $scriptProperties['sortDir'] : 'ASC';
$c->sortby($sortBy, $sortDir);