Getting NationBuilder to show survey's in FieldEdge is a little strange. The survey's need to be attached to a page on your website (with the "Survey" page type).
Here's a quick vide overview to fixing this issue:
For a survey to work in FieldEdge it must be connected to a webpage (not just exist in the people section of your nation). This page can be published or it can be unlisted.
First, follow the steps to create a new page on your site. This process works the same regardless of what type of page you’re creating.
1. Go to Website in the left-hand menu and click on the website you'd like to create the page on. Note that you can attach it to any website and it will appear in FieldEdge
2. Click +New Page, give your page a name and select the Survey page type
3. Ensure the page status is set to Unlisted (to avoid it from being shown on your website)
3. Be sure neither of the "show in nav" tick-boxes are ticked
5. Click the “Create new page” button.
6. You’ll be taken to Survey settings > Basics. Select the survey in question from the Survey dropdown.
7. Finally, be sure to save! (you can ignore all other settings)
The survey should now appear in FieldEdge.
For more on creating surveys for use in FieldEdge, see: http://docs.fieldedgeapp.com/en/articles/858302-add-a-survey