Nuclear power: 500MW is considered a "small/compact" nuclear plant, costing about $1.5 billion with a footprint of a few acres with a lifetime of approx. 40 years.
A nuke plant will cost far more than what you are claiming. Costs currently are running between $5000-8000/KW. And that is just to build it - you didn't consider operating costs at all which are far more substantial for a nuke plant than a solar one. The waste disposal alone is a huge cost that doesn't exist with solar.
Why the hell are people investing in solar? The economics make absolutely no sense whatsoever.
Really? You can't figure this out? Solar has no failure modes that can render a location uninhabitable. Solar has no serious fuel waste disposal problem. Solar has no weapon proliferation risk. Solar is insurable by private companies rather than nation states. Solar doesn't require getting fuel from elsewhere. Frankly solar has quite a lot to recommend it over nuclear in many (though not all) cases. Nuclear has its advantages but let's not pretend that it doesn't have some very substantial drawbacks.