What do you do against someone wearing chainmail over their whole body, with padding underneath?
Club them. The padding will take some of that force from the blow, but the chain won’t do anything against blunt force trauma. Strictly speaking, maces, warhammers, flails, and anything vaguely club like. In a modern setting, a sledgehammer wouldn’t be a bad solution.
Beyond that, axes might not break the chain, but they will deliver considerable kinetic force, and should be able to break bones. Some polearms, including spears, are also a real option. Again, the chain should keep it from puncturing the victim, but it should still deliver enough force to do unfortunate things to their bones. Also, with both the axe, and polearms, there’s a distinct possibility the blow will damage the armor, and the weapon.