Haddin here from the Shopify Retail team!
The Tap & Chip reader that is available on the United States hardware store is only compatible with US Shopify stores, and may also experience some issues processing Canadian cards with the reader; this is the same for all hardware offered on our US store. It is because of this that we advise against using the US Tap & Chip in Canada, and that we do not officially support doing so. It is also important to note that you are only able to purchase hardware from your respective hardware store, as we do not ship to Canada from the US store.
That being said, we do offer separate readers in our Canadian market, which you can find on our Canadian hardware store, here. If you require the tap functionality for your business, I recommend taking a look at the Moneris® debit and credit terminal available on our CA hardware store - however, you will need to be using the Shopify plan or higher in order to use the Moneris terminal.
You can see the differences between all of the card readers that we offer in this Help Center article.