Neutral setting. No retarded "saburz only", because that kind of fighting does not reflect common sense. The setting is an empty basketball court. It's assumed that Nox is at the end of their storyline, ghosts intact, and that Kun has Kun-mulets.
I think Nox can tank Kun's amulet blasts quite well given that they shrugged off Thanatons lightning. I'd give them a better chance of overpowering Kun than Kun does them.
I wouldn't say they're much stronger than Thanatons lightning, but I'd think that because Nox swatted Thanatons lightning aside one-handed and even when they let Thanaton charge up and hit them without resisting they just walked through it unharmed.
Kun's blasts have blown through walls and a Leviathan as I believe their top destructive feats, while Thanatons lightning cracked the floor with just the impact of hitting Nox. I wouldn't say theres much of a disparity there. Even if Kuns blasts are superior to Thanatons lightning, the ease with which Nox handles Thanatons lightning makes me think they can handle the amulet blasts with difficulty.
Furthermore, Thanaton was able to shred through Nox's barrier while it was empowered by 2 Sith Lords, which is indicative of his power. That Nox walked through his best efforts at the end of the game suggests huge defensive capabilities imo.
I'd have to give it to Nox too although it would be a tough fight. His battle with Thanaton was incredible and the fact that he's got those 4-6 ghosts in him make him even more formidable, as well as better at defending against force attacks.