Business & farm

Code 768 Refers to the Earned Income Credit, Code 766 refers to other tax credits that might be applicable. Even if these codes are bigger than your refund, it doesn't mean that your refund should be equal to these codes. 

The overpayment or "refund" consists of payments and/or credits in excess of your tax liability. 

What does "tax liability" mean? Is that the amount I still owe?

See the image below for reference. This is an example of a summary breakdown. You can find a breakdown of your tax summary on the left panel of your TurboTax screen under Tax Tool> Tools> View Tax Summary