If you would like to change how reviews are sorted on WooCommerce product pages, there are at least two ways to do it. Let's discuss these two approaches in more detail.
1. Standard WordPress Settings
First of all, it is possible to do so using the standard WordPress functionality. Reviews in WooCommerce are essentially WordPress comments with additional meta data. So, the sorting settings for comments will also apply to WooCommerce reviews. The disadvantage of this option is that the sorting settings will apply globally to WordPress and not just to reviews on WooCommerce product pages.
Go to Settings -> Discussion menu (in the standard WordPress menu) and find options “Break comments into pages with X top level comments per page and the last/first page displayed by default” and “Comments should be displayed with the older/newer comments at the top of each page”. You can control how reviews are sorted and displayed on product pages by modifying these options.
2. Lazy Load Reviews Settings
Our plugin offers an option to display reviews with Laze Load approach. It replaces the standard WordPress pagination and shows additional reviews after clicking on "Show more" button. If you use Lazy Load reviews setting, it is possible to set how reviews are sorted there.
Go to Reviews -> Settings -> Review Extensions and use "Default Sorting Order" option to configure sorting. Please do not forget that this option will apply only when Lazy Load reviews setting is active.
With this option it is possible to not just set the default sorting of reviews but also let customers change it on product pages themselves.