You can add a chart widget to your dashboard from the Add Widget menu.
Next you can choose to add a chart for a Scorecard Item, Initiative Item, or a chart that you've already created in the Reports section.
In this example we'll choose Scorecard Item and then choose an item to add to the dashboard.
When we click Add a chart is added to the dashboard.
From here, you can configure your chart to show your data in a variety of ways. This is the same process as configuring charts in the Dashboards section, and both are covered in the Customizing Charts article.