Can I see analytics of size chart usage for my shop?

Yes!

For shops on paid plans (premium or ultimate), you will have 2 ways to see analytics data.

1. First, you can click on the "Analytics" button on the top of dashboard

From here, you can see how many times size charts have been clicked on the product pages. And see the click through rate.

2. The second way of seeing analytics is integration with Google Analytics. Again this is only available for paid plans.

Go to settings, and click on advanced

Scroll down until you see the Analytics section. You will need to have Google analytics enabled on your Shopify shop first for the integration to work. After that, there will be custom events (as shown in the table) send to your Google Analytics account!