Most places with high solar insolation values also tend to come with high cooling costs. Arizona and Southern Nevada are perfect for this application, but my first approximate guess is that HVAC would eat all of, if not more than, the benefits.
The main reason NV and AZ don’t have significantly larger data center foot prints is mainly just from lack of cheap energy (data centers run 24/7 at a pretty constant load so solar isn’t a good fit).
When I last looked into it, CoLo space in Vegas and Phoenix at small scale has prices competitive with other locations. The biggest downside is distances to major IXPs. So using them is contingent on latency goals.