Answer: nestable

AnswerCrossword Clue
NESTABLESpace-saving, in a way
nestablecapable of being fitted closely together
nestableany place used by an animal for rearing its young
nestableto fit one within another
nestablestructure of grass, twigs, etc., prepared by a bird for its eggs
nestableto settle in a nest
nestablegroup of things fitting tightly together