The estimation of excess cancer deaths for Chernobyl and Fukushima is based on exposure results and the LNT model of accumulated dose response instead of actual observed cancer incidences, because it's impossible to actually assign specific incidences of cancer to specific causes. Thus, the counts for deaths caused by Chernobyl--the only nuclear power plant to cause significant death--will include deaths that have yet to occur.

The total estimates for deaths to nuclear power, even including the use of Hiroshima and Nagasaki atomic bombs, struggle to amount to a million, even if you start using the high outlier estimates of anti-nuclear groups.