Good to know, I suppose?
Sure, if you ignore the fact that I said appropriate amount of nuclear weapons. As in more than one. And not "a" nuclear bomb. You quoted the part and somehow still wanted to argue, I guess?
And Nico doesn't send monsters to the core of the sun. She sends them to the middle layers, generally. Which is significantly less hot and likely with even less pressure. The sustained heat and pressure would be a good counter if Nico didn't use her sun fire attack to vaporize Level 5 Ella's monster body. And unless it was less durable than A Class monsters. You can indeed argue that enough Nuclear weapons can kill A Class monsters. Assuming, you can get it up to the same level. The keyword that you're likely going to ignore again is "assuming".
Also, let me highlight what I said. Since, maybe I'm the crazy one here.
Maybe I should highlight the certain Level 4s and A Class monsters part too? Nah, it's fine.