As nouns the difference between stacks and chimney
is that
stacks is while
chimney is a vertical tube or hollow column used to emit environmentally polluting gaseous and solid matter (including but not limited to by-products of burning carbon or hydro-carbon based fuels); a flue.
As verbs the difference between stacks and chimney
is that
stacks is (
stack) while
chimney is (climbing) to negotiate a chimney (sense #4) by pushing against the sides with back, feet, hands, etc.