Delocalization transitions underlie many important problems in condensed matter physics, particularly unconventional superconductivity. The observation is that a system near a localized state (like a Mott or Kondo insulator), undergoes a small to large Fermi surface change that coincides with the highest superconducting critical temperatures. The implication is that understanding the mechanism behind the delocalization will point to the mechanism of superconductivity itself. We explore this question in the unconventional superconductor 4Hb-TaS2, a system that interleaves Mott-like and metallic layers, and show that there is indeed a Fermi surface transition in a flat band that is correlated with the appearance of bulk superconductivity. We show that there is a surprising origin to this delocalization: disorder. Although counter-intuitive at first, we explain that this process may be more common in nature than previously thought.