My mistake - I reread your post, and I understand you to be saying that a nuclear plant generates a 10^6 (USA million) times as much long-lived radioactive waste as a coal plant for each unit of energy.

As everyone acknowledges, coal plants don't contain their waste, and fly ash has bad chemical, medical, and ecological properties aside from its radioactivity. Everyone fears nuclear waste and requires it to be contained in nearly impervious vessels with century long management plans. Those same people happily let the coal plants just pump their wastes into the air and discharge captured fly ash into ponds and piles on the ground.

Coal also produces many times more fly ash by volume and mass than nuclear plants produce high-level long-lived wastes.

Luckily even fossil-fuel power generation is moving away from coal in favor of natural gas plants right now, which are cheaper and cleaner (still CO₂ though).

More about fly ash as an underappreciated pollutant:

https://www.sciencedirect.com/science/article/abs/pii/S00128...

https://en.wikipedia.org/wiki/Kingston_Fossil_Plant_coal_fly...

If you did, it's not very clear.

The OP to which you replied didn't say that coal is more radioactive than spent nuclear fuel; but that radioactive waste's volume is much smaller than the fly ash produced by a single coal plant in a decade.

Is fly ash per kg more radioactive than nuclear waste? No. But you did acknowledge that the coal plant emits its waste into the atmosphere, unlike a fission plant, which I think is the more relevant point.