overrated, nukes tend to blow up quite efficiently so there isn't much lingering fallout left behind
reactors meanwhile don't burn radioactive isotopes well since neutron flux isn't large enough to just break everything up & you get much more fallout from reactor accidents or spent fuel spillovers
consider that when russians experimented with using nukes to dig canals, one such crater is now a lake where locals catch fish and pick mushrooms with no ill effect
https://bellona.ru/2002/12/24/atomnyj-kotlovan/
also consider that background radiation in hiroshima and nagasaki was back to normal but high in a year (most naturally radioactive places where people live are more radioactive than hiroshima and nagasaki at that point), and was already perfectly survivable for going through mere couple days after
now if you specifically wanted to create fallout.. you make a dirty bomb. go to fucking chernobyl and get some corium, then put it into conventional explosive.