If it is possible that something will happen, you can say that there is a chance that it will happen or a chance of it happening.
There is a chance that I will have to stay longer.
If we play well there is a chance of winning 5-0.
If something is fairly likely to happen, you can say that there is a good chance that it will happen.
There was a good chance that I would be discovered.
We've got a good chance of winning.
If something is unlikely to happen, you can say that there is little chance that it will happen. If you are sure that it will not happen, you can say that there is no chance that it will happen.
There's little chance that the situation will improve.
There's no chance of going home.
If someone is able to do something on a particular occasion, you can say that they have the chance to do it.
You will be given the chance to ask questions.
Visitors have the chance to win a camera.
If something happens by chance, it was not planned.
Many years later he met her by chance at a dinner party.
If you say that something happens by chance, you are not saying whether it is a good thing or a bad thing. If something good happens without being planned, you refer to it as luck, not ‘chance’.
I couldn't believe my luck.