It is comparing the cost of nuclear fuel to generate a kWh of electricity vs the cost of a solar to generate a kWh of electricity in what is a great location.

So it excludes the entire construction cost of the nuclear plant as well as operating the nuclear plant. It also excludes any sort of storage costs for running the grid with solar. However we are talking about the UAE for solar, so cloudy days without sunshine are basicly not a thing. So you really only need a nights worth of batterie storage. Most consumption happens during the day, so we are talking maybe a third of total generation would need to be stored. So for a MWh of daily use and $333/kWh. Given that you need 333.3kWh of storage, which costs $111,000 total.

Since this is only fuel costs thou and the nuclear plant has to be built as well, which is not included in fuel costs. So lets look at what 1MWh a day would cost in terms of nuclear power plant. Olkiluoto3 was just finished for $12billion for 1,600MW or $312,500 for a MWh per day.

So in this case you are basicly betting that a nuclear power plant lasts three times longer then the battery storage and battery storage costs are not falling, which is propably not going to be the case. Also a bunch of technologies do not care too much about when they get power. If you for example have super cheap electrolysis to produce hydrogen during the day, that is an intressting use case. Also grids propably have more then just one power source, so stuff like wind power, hydro and so forth might also be options in some grids and solar prices are falling over time.