This article revisits the Cold War-era concept of ‘catalytic nuclear war,’ considered by many as unworkable, and reconceptualizes it in light of technological change, as well as improved understanding of human psychology and other factors. It argues in the modern digital era, the catalyzing chain of reaction and counter-retaliation dynamics set in motion by the deliberate action of a non-state or third-party actor is fast becoming a more accessible and plausible alternative to acquiring a nuclear weapon or manufacturing an improvised atomic device – or ‘dirty bomb.’ The article concludes that artificial intelligence (AI) technology is creating new – and exacerbating old – escalation pathways that risk catalyzing accidental nuclear confrontation between nuclear-armed powers, particularly under irrational (or sub-rational) conditions. Are existing notions of accidental and inadvertent nuclear escalation still relevant in the age of AI and autonomy?