I can see nuclear-powered propulsion for long-term space flight. What would be advantage of nuclear propulsion for an ICBM? Seems a gimmick more than anything.
Nuclear powered nuclear misiles: now fortified with even more radioactive material
Unlimited range and endurance, a problem for air breathing or rocket powered cruise missiles. The ingress route could be insanely convoluted to evade detection and tracking.
Fire it from Siberia and route it to come up from Mexico? The Russian deployment strategy would be fascinating to know.