It doesn’t look like Google has an API available for the shopping lists, so I can’t think of an easy way to display it directly in a tile. That being said, you could use a Hyperlink tile which links to:
https://shoppinglist.google.com/
It also looks like Google blocks embedding the shopping list page as an iframe, so you’ll have to use the Open in Same Window or Open in New Window option (Open in Modal is blocked by Google).