The way I see it, super is one step above and is greater than nice. Nice would be equivalent to fine, satisfactory, pleasant, good. Super on the other hand goes above and beyond meaning very good, very pleasant, etc.
This is the way I see it. If you still think that your translation should be accepted, you can click "Report a problem" at the bottom of the page and add your alternative translation. I assure you that these reports are periodically sorted through and as time goes on, more and more alternative translations are added.