Nosto for Shopify supports ratings and reviews powered by Yotpo. In order to begin leveraging Yotpo ratings and reviews in Nosto, you'll need to install Yotpo's app for Shopify.
Once you've installed the Yotpo for Shopify app, you'll need to follow their guide on setting up "rich snippets" in Shopify.
Once you have installed and configured Yotpo on your Shopify store, Nosto begins collecting the rating and review metadata automatically. There is no additional configuration required on Nosto's end.