ACE Editot TV-type. Plugin listen OnDocFormRender event and must be execute after Ace plugin, so set priority something like 10 or higher. TV type must be textarea.

acetv.plugin.php

<?php
//Apply ace editor to TV with id 5 and 7
$tvs = array(
    array(
        'id' => 5,
        'height' => '600px',
        'mimeType' => 'application/json'
    ),
    array(
        'id' => 7,
        'height' => '300px',
        'mimeType' => 'text/html'
    )
);

if ($modx->event->name != 'OnDocFormRender') {
    return;
}

if ($modx->getOption('which_element_editor', null, 'Ace') !== 'Ace') {
    return;
}

$script = '';
foreach ($tvs as $tv) {
    $id = is_array($tv) ? $tv['id'] : $tv;
    $height = isset($tv['height']) ? $tv['height'] : '';
    $mimeType = isset($tv['mimeType']) ? $tv['mimeType'] : '';
    $tvId = '#tv' . $id;
    $setHeightScript = !empty($height) ? 'this.style.height="' . $height . '";' : '';
    $aceScript = 'MODx.ux.Ace.replaceTextAreas([this], "' . $mimeType . '");';
    $script .= 'Ext.each(Ext.query("' . $tvId . '"), function() { ' . $setHeightScript . $aceScript . '});' . PHP_EOL;
}

if ($script) {
    $modx->controller->addHtml('<script>Ext.onReady(function() {' . $script . '});</script>');
}