Water is the biggest challenge. All the city's waste water will need to be recycled. That's doable, but to compensate for evaporation they might also need to pipe in water from coastal desalination plants if they cannot harvest enough rain. That's a lot harder.

I'd be concerned about their ability to handle sewage which requires water for processing. Burj Khalifa has to have its sewage trucked out daily because nobody bothered to plan for the load on the Dubai infrastructure.

How do you cool a nuclear reactor without water?

I guess you don't. That's why they're concerned.

The Palo Verde Generating Station is a nuclear power plant located near Tonopah, in western Arizona. It is located about 72 km due west of downtown Phoenix, Arizona, and it is located near the Gila River, which is dry save for the rainy season in late summer.

The power plant evaporates the water from the treated sewage from several nearby cities and towns to provide the cooling of the steam that it produces.

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

Night radiative cooling, the Cosmic Background radiation temperature is 4 degrees K.

This can be great for houses as well see https://www.google.com/imgres?imgurl=http%3A%2F%2Fwww.solarm...

Sewage