This is not a particularly good example of the economics of solar. For starters, it's a concentrated solar thermal plant, which is significantly more expensive than a photovoltaic plant. There's a reason most everybody has given up on solar thermal. So sure, this plant cost $9 billion, but two years ago SunPower sold a 579 MW photovoltaic power plant to Warren Buffet's Mid-American energy company for $2-2.5 billion -- and aside from being two years ago, that's with solar panels guaranteed for 25 years from a company widely regarded as one of the most expensive in the business. Based on similar deals and using solar modules from a cheaper supplier, that same plant now would likely cost more like $600-700 million to build and sell for something like $800-900 million.
And when you're talking about the footprint of nuclear, don't forget to count the land dedicated to mining uranium, much of which comes from land-hungry strip mines, and processing waste (both from the plant and the mining operations). Those plots of land are just as useless as the ones the plant itself sits on. Also, don't forget that nuclear uses an enormous amount of water, rendering it rather impractical in many desert regions.