It’s really not, nuclear inherently requires extreme costs to operate. Compare costs vs coal which isn’t cost competitive these days. Nuclear inherently need a lot more effort refining fuel as you can’t just dig a shovel full of ore and burn it. Even after refining you can’t just dump fuel in, you need fuel assemblies. Nuclear must have a more complicated boiler setup with an extra coolant loop. You need shielding and equipment to move spent fuel and a spent fuel cooling pond. Insurance isn’t cheap when mistakes can cost hundreds of billions. Decommissioning could be a little cheaper with laxer standards, but it’s never going to be cheap. Etc etc.
Worse, all those capital costs mean you’re selling most of your output 24/7 at generally low wholesale spot prices unlike hydro, natural gas, or battery backed solar which can benefit from peak pricing.
That’s not regulations that’s just inherent requirements for the underlying technology. People talk about small modular reactors, but small modular reactors are only making heat they don’t actually drive costs down meaningfully. Similarly the vast majority of regulations come from lessons learned so yea they spend a lot of effort avoiding foreign materials falling into the spent fuel pool, but failing to do so can mean months of downtime and tens of millions in costs so there isn’t some opportunity to save money by avoiding that regulation.