The entire case is dovetailed together at the sides. The base surround and the top surround is also dovetailed. the only nails are holding the moldings to the underside of the top surround and the top of the bottom surround, which is traditional. Everything else, like the Cedar bottom boards, either fits into grooves or is free floating like the top center piece within groves to allow for expansion and contraction. This style of chest has been made in one form or another but based on the same ideas, since the middle ages. The joinery is timeless, at least as far back as Egyptian times, and probably before that if any has survived.
John