[french fries]

My experience has been that resting a perfectly crispy chicken in a sealed environment - well you might as well peel that rubber skin off before serving because it's not crisp anymore.

Yup. And it's the same with a steak by the way. That crispy charred crust you develop by grilling/sauteeing at high heat will become moist and soggy from the vapors when rested in a sealed environment.

After grilling, I usually turn off the grill, open it so it's not too hot inside, then close it and rest the grilled items right on the closed, turned-off, still warm but not too hot grill.