I agree it would have been better to phase out coal before nuclear, but it's not correct to say that there was a switch from nuclear to coal.
The switch was from nuclear to renewables. Coal was stable for a long time, and is now decreasing. Coal is currently scheduled to be phased out by 2038.
Source: Quick Google image search for the power sources over time plots.
> Coal was stable for a long time, and is now decreasing.
Over which time period?
The stats in the article they link indicate a switch from 21 to 27% for coal, from 52 to 44% for renewables, when comparing the first halves of 2020 and 2021. If there's a downward trend, it's less than obvious.
A time period of one year is too short to draw trend conclusions, it really doesn't tell us anything about the (long term) trend. It's like using the weather from last year and comparing it to this year to say something about the climate. Look at 5 years or 10 years to spot energy trends.
The switch was from nuclear to renewables. Coal was stable for a long time, and is now decreasing. Coal is currently scheduled to be phased out by 2038.
Source: Quick Google image search for the power sources over time plots.