For your AWS Trusted Advisor integration dashboard to populate with data, you'll need to 1) configure support permissions and 2) have an upgraded AWS support plan.
1) Support Permissions
In the IAM Console, add support:* as an action in the policy document text box:
2) AWS Support Plan
The Datadog Trusted Advisor Dashboard needs access to the full set of AWS Trusted Advisor checks. AWS makes these only available for upgraded AWS support plans. Make sure that your AWS plan includes full access: