You can put a shortcut to it on your homescreen but I don't see any way to make it a widget where you can actually view the data on your homescreen. I'm sure there are apps you can download for that, but you were asking about stock. To make a shortcut, go to the app drawer and click on the widget tab up top. Scroll through until you see Settings Shortcut and place that on your homescreen. You will then get to choose which setting it links to and you can choose data usage.