"There is a good chance that the Prime Minister of India will visit Australia". What does this statement imply?
It is more likely that the Prime minister will visit Australia.
The word "chance" refers to the possibility of an event occuring or not. It does not, however, ensure the happening of that event. The term "good chance" indicates that it is more likely that the event shall occur.
So, the above statement means that the Prime Minister of India may or may not visit Australia, but the term "good chances" indicates a high possibility of occurrence of the event.