However, the risk is distributed differently, with coal plants emitting pollutants on a fairly regular basis, while nuclear power plants have a quite small risk of something quite bad happening.
And in addition to the regular, consistent pollution, coal plants also have a small chance of very bad things happening. Except that the the chance is higher than for nuclear plants, and the damage is greater.

The worst radiological disaster resulting from power generation in US history was a coal fly ash spill in Tennessee, in 2008, and that's even before you account for the even worse chemical toxic effects.