*UPDATE*: It works. Here's the relevant part from my FreeNodelet:

<!-- Syntax HL -->
<style>
p.code {
  margin-top: 2px;
  margin-bottom: 2px;
  background: #08080f;
}
code.prettyprint {
  background-color: #112 !important;
}
</style>
<script src="https://code.jquery.com/jquery-3.1.1.min.js"></script>
<link rel="stylesheet" href="http://blogs.perl.org/mt/mt-static/plugin
+s/GCPrettify/prettify.css" type="text/css" media="all" />
<script src="http://blogs.perl.org/mt/mt-static/plugins/GCPrettify/pre
+ttify.js"></script>
<script>
$(document).ready(function () {
    $('p.code').wrap('<pre><code class="prettyprint"></code></pre>');
    $('p.code  br').remove();
    window.prettyPrint();
});
</script>
[download]

You might need to fix some colours, e.g. like me:

span.pln { color: #eee }
span.pun { color: #ffd }
span.typ { color: #e4e }
span.lit { color: #2dd }
span.com { color: #f11 }
[download]

I also used

$('p.code').not('.pmsig *').wrap('<pre><code class="prettyprint"></cod
+e></pre>');
[download]

to skip highlighting in signatures.

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
[download]