The way I see it, "chance" has to do more with unexpectedness in quite a number of cases. Consider the following sentence:
Leave nothing to chance.
That is "study whatever you are up to carefully and watch out".
On the other hand, "opportunity" implies more than just chance:
For more than two centuries, America has been a beacon of hope and opportunity for people from around the world.
I found this nifty explanation by an Englishman online:"A chance is available in a situation where you are surprised or you had not expected it to happen. In a sentence like: As we were in the city at the time we had a chance to visit the museum.
Here this is something that we had not planned. In this sentence: If children work hard at school, they have an opportunity to go on to higher education. Here this is something that is planned and can also lead on to something else."
Student or Learner