The way I saw it they more or less smothered us in that first part of the second half, pressed higher, didn't allow us to play out. Got sustained attacks, we didn't find a way out. They put on Kante, changed the central midfield, but also upped their pressing.
I'm not sure what Nuno could have done to react. We had no players on the bench capable of turning us into a more press resistant team.
Seeing at this is the Ndombele thread. What we want in a situation like that is for one or two opportunities to counter attack. Ndombele, Lo Celso, possibly Kane or Hojbjerg getting out from pressure and launching a counter attack. As we saw from the second goal trying that comes with risk, but I think we have to try. We didn't get that successfully from any of our players really. That's a valid criticism of Ndombele, but should come with the realisation of that being a difficult and risky thing to do. Chelsea are really good at keeping that film happening.
I guess one option would have been Skipp on earlier, try to just sit back even more. They scored 5 minutes into the half. Not sure replacing Ndombele with Skipp a minute or two into the second half at 0-0 would have made us happy.