This is a propaganda talking point from anti-nuclear activists that is misleading and/or false. There are several misleading or incorrect levers used to justify this statement. The first sleight of hand is looking at the cost of headline capacity of intermittent sources. The second sleight of hand is the assumption that our current (insane) energy market pricing structure is reasonable. There's also the significant caveat that intermittent generation will depend on backstopping by carbon-emitting sources like natural gas. Finally, even reducing "capacity factor" to a single number is garbage. The minimum production really matters, and for intermittent sources, the minimum is zero.

Which is all to say -- it is not clearly and obviously correct to say that nuclear generation is cost prohibitive, and repeating it as if it were is a signal of bad faith.