> Nevada is a sovereign state

I think this is why you're getting downvoted. A "sovereign state" is a state that has the highest authority over a territory, but Nevada remains subject to US Federal law.

(I do not know to what extent US states have leeway on banking regulations)

States are indeed the highest authority over a great many matters within their territory. They share sovereignty with the federal government. That is a central feature of our system.

The US has a dual chartering system where banks can be chartered by a state regulator or the US comptroller of the currency. In either case they are subject to the same overlapping set of state and federal laws and mostly the same regulations, just applied by different regulators.

https://dfpi.ca.gov/the-dual-chartering-system-and-the-benef...