can we keep brownies in the chiller?

Just leave them overnight in the container. Parchment paper between the layers is a good idea. Unless you're are looking to store for a prolonged amount of time why got to the trouble of freezing. i find they never last long enough to make it to the freezer

I bake brownies or blondies every week. Although I give most away within a day or two of baking, sometimes I have too much to give away immediately. I keep brownies in the fridge and freezer - as airtight as I can get it. If I'm keeping them in the fridge, I wrap in parchment then tightly in plastic wrap. It keeps in the fridge for about a week. When I'm ready to eat, I just let them come to room temp on the counter before eating. If I'm going to freeze brownies, I wrap in parchment then plastic wrap then put in a freezer storage bag. When I'm ready to eat, I put frozen ones in the microwave for a few seconds to get soft and mushy. But they are also totally delicious straight out of the freezer! They don't freeze rock sold - I think it has to do with all the fat. I'm told you can keep brownies in the freezer for several weeks - I've never had occasion to test that theory.

Either way is fine. An FYI, I'd suggest placing a piece of parchment paper in between the layers of brownies, if you have them stacked, to keep them from sticking together.