The Ising-QCD effective action is introduced in order to study critical fluctuations in high-energy nuclear collisions. The order parameter in this description is the baryon-number density, a conserved quantity, compatible with the slow mode of the QCD critical point dynamics. We argue that finite-size scaling is the origin of critical fluctuations in the form of a fractal structure in the finite system. As a result, critical intermittency in nuclear collisions is a finite-size scaling phenomenon, linked to the QCD critical point, and may provide us with a route to observation of critical fluctuations in QCD matter.