Does il y a des chances require the subjunctive?
Yes, il y a des chances requires the subjunctive:
Il y a des chances qu’il pleuve ce soir.
There’s a chance that it will rain tonight.
À noter : There’s some disagreement about these types of expressions, but it comes down to possibility vs probability: the former requires the subjunctive, the latter the indicative. In my (and many others’) view, des chances is on the possibility side of the scale, which calls for the subjunctive.