I found a way to do this and since I couldn’t find it anywhere else I thought I post it here, even though this question where asked a few month ago:
<?php $tags = wp_get_object_terms($image->pid,'ngg_tag') ?>
<?php foreach ( $tags as $tag ) : ?>
<a href="<?php bloginfo('url'); ?>/tag/<?php echo $tag->slug; ?>"><?php echo $tag->name; ?></a>
<?php endforeach; ?>
(This just prints the tags as links to https://example.com/tag/example-tag, I guess that the links won’t work but you get the point :D)
This would be added in your ngg gallery template, inside the loop for printing out the images.
