As of 2018 there was about 1100 gigawatt of generating capacity, with nuclear about 9% of that total. That less than one-tenth of installed capacity can likely be shut down in a controlled fashion during the slack spring season. Some of that nuke capacity has been retired in the last two years since that 2018 reference published.
Summer peak demand usually is around 750 to 800. This might be more demanding, depends how maintenance shutdowns had been scheduled, and whether any deferrals occur during the Spring. Straight gas turbine peaking units that usually only run hours a day at least have NG available at rock bottom prices for now.
Your logic on Texas power fails in the face of the exponential disease growth curve.
One half of all disease cases happen in the last round of exponential growth.
There simply will not be enough well or recovered people to run all the natural gas peaker plants when, not if, the disease takes out the control room staff for Comanche Peak and STP nuclear plants.
The simple reason is half of all the power system staff who will get sick, will do so _AT THE SAME TIME_.
This is why the mantra “Flatten the Curve.” It’s not just for the medical staffs.
And because the electric power generation plants are strategic national assets. You simply CANNOT run the the remaining staff to death and risk long term damage to the power plants.
Rolling black outs will be the unavoidable reality we face for several months.
Lots of the decommissioned nuts have been replaced with CCGT.