PSG is a very good team and even though they lost to Botafogo I imagine Chelsea will have studied how Botafogo played very well to make a good plan. At first glance Chelsea doesn't have much of a chance, but this is football, anything can happen, although for me PSG is unstoppable and it's very difficult for them to lose, they are playing wonderfully.
PSG would have also corrected the mistake that made them lose to Botafogo. A close look at the statistics of that game showed that PSG had just two shots on target out of sixteen shots. The French side also dominated in ball possession but the Brazilian side were good defensively. Chelsea can adopt a defensive approach by crowding the midfield and defence, then relying on the striker for goals.