There is a trick, you can multiple build simultaneously. Or better with a slight delay, so that construction crews (which do separate phases of construction) can move between projects and use experience gained in one build in another build.
Nuclear construction requires highly skilled workers doing very high quality work. One of the biggest problems with nuclear construction in U.S. and Europe is that last significant builds have been done around 1985, companies doing nuclear construction closed or moved to other products, or moved to maintenance, upgrades of power plants.
> There is a trick, you can multiple build simultaneously.
That trick does not work for smaller countries which can't afford/don't need to build a big number of reactors. Or you have to outsource to a foreign builder which does not seem to be a best idea in today's world.
Anyway, the original claim was "You can put up a plant in 5 years without erroneous regulation". It's simply not possible to do that. If you depend on continuous availability of highly skilled workers, you also have to account for their (initial and continuous) training. In addition you also have to maintain the staff which does the planning and permitting.
https://en.wikipedia.org/wiki/Barakah_nuclear_power_plant
Nameplate capacity 5600 MW
Construction began
Unit 1: 19 July 2012
Unit 2: 16 April 2013
Unit 3: 24 September 2014
Unit 4: 30 July 2015
Commission date
Unit 1: 3 August 2020
Unit 2: 14 September 2021
Unit 3: 10 October 2022
Unit 4: 23 March 2024