They have totally different meanings. Look them up in an English-English dictionary and you'll see.
Probability means likelihood.
Opportunity refers to the circumstances allowing you to do something.
The only thing that they have in common is the word 'chance'. 'Chance' has several meanings, and 'opportunity' is a synonym of one of its meanings, and 'opportunity' is a synonym of a different meaning. There is no overlap between 'opportunity' and 'probability'.