The fabrication of chiral structures using achiral building blocks is a fundamental problem that remains a challenge in materials science. In this work we present a molecular dynamics simulation study of nonconvex polygonal platelets, interacting via soft-repulsive interactions, that are confined in two-dimensional space. These particle models are designed to promote, even at moderate densities, a natural offset displacement between the edges of neighbouring particles. In particular we demonstrate that nonconvex platelets exhibit macroscopic chiral symmetry breaking when the symmetry of the particles equals (or is multiple of) the number of nearest neighbours in the condensed crystalline phase, corresponding to the situation of platelets with 4-, 6-, and 12-fold symmetries.