usually i would agree to the "increase supply to lower the cost" story, but in the case of energy it's a bit different, because the Energy market uses the merit order principle, which means that whenever the nuclear reactors run, electricity is just as expensive as if nuclear reactors were the only source of electricity, and if they don't run, only then prices drop.
so, you're only getting cheaper prices by not needing nuclear energy. but, for nuclear plants, building them is a huge part of the cost, and they're typically heavily subsidized by taxes, which means an (unnecessary if not used) burden on the taxpayers.