Since the video.js player with the Nuevo plugin makes use of custom CSS skins, you must also load a custom CSS stylesheet for the Ima plugin.
Code snippet
<head><!-- Load dependent stylesheets. --><link href="path/to/videojs/videojs.css" rel="stylesheet"><link href="path/to/videojs/plugins/ima.css" rel="stylesheet"/></head>
<body><video id='my_player' class="video-js"><source src="PATH_TO_YOUR_CONTENT_VIDEO" type="YOUR_CONTENT_VIDEO_TYPE"/></video>
<script src="//imasdk.googleapis.com/js/sdkloader/ima3.js"></script><script src="/videojs/video.min.js"></script><script src="/videojs/plugins/videojs-contrib-ads.js"></script><script src="/videojs/plugins/ima.js"></script><script src="/videojs/nuevo.min.js"></script>
<script>const player = videojs("my_player", {license: "key"});player.nuevo();player.ima({adTagUrl: "YOUR_AD_TAG"});</script>Please note, the IMA plugin and IMA Sdk is a project by Googleads developers. Nuevodevel is not responsible for any possible issues with the display of Google ads.