The Nudge tool is available in the Brushes menu and can be configured to any of the slots in your tool wheel or tool bar. To do this:

 

1. Tap the slot you want to configure. This will highlight and activate it.

2. Tap the slot again to open the Brushes menu.

3. Find the Nudge tool in the Tools section under My Brushes. Tap to select it.

4. Close the Brush Menu by tapping anywhere outside of it. You’ll see your tool has been changed to the Nudge tool and is ready for you to use.

If you’d like more information, you can learn more about using Nudge with this tutorial, or check out this tutorial here to learn more about configuring your tools.