Can buttermilk biscuit dough chill overnight? Thanks!

Yes.

If it's yeast based, it shouldn't be a problem, just warm the dough up to room temperature before you bake.

For baking soda and baking powder, I'm something of a coward and wait until just before baking before I add them in. Thanks Kristen for letting us know we can leave the baking powder in overnight - love learning something new.

What kind of leavener does it call for -- baking powder or baking soda? I think if it's baking powder, you should be fine -- and a good chill will probably help them rise even better!