The time from inception to going online for a new Nuclear reactor is in the range of 15-25 years. Of course we could attempt to shorten that, but that would probably mean compromising on safety
It also takes 20years for a tree to grow, so I guess we should stop planting trees too. Good logic.
The rest of what you are saying is ignorant at best. "Global construction capacity" is constrained to current levels. How convenient that we can only build exactly the number of nuclear reactors we are currently building. But we can build an unlimited amount of solar panels, wind turbines and "hyrdo."
How long do you think it takes to "build hydro?" If you ignore any and all environmental costs of flooding valleys, then sure I guess you could do it pretty quickly, you'd probably have to relocate hundreds of thousands of people, but sure that sounds more feasible then building a nuclear reactor.
Current Nuclear energy production is non-renewably because of cold-war era treaties against enrichment and breeder reactors. The timeline for nuclear fuel to run out if you allow breeders, is after the sun burns out. So that's a non-issue. Not to mention other theoretical sources of nuclear fuel that we don't bother even looking at because it's cheaper to burn more coal.