Why I Think Homelander Could Survive a Nuclear Bomb
I think Homelander could survive a nuclear bomb. Vought's contingency plan was Ryan, not an atomic bomb, a hydrogen bomb, or a neutron bomb.
Another detail is that Maeve tells Butcher about a weapon that could kill Homelander because they believed it had killed Soldier Boy. That option wasn't a nuclear bomb, which probably means they had information suggesting it wouldn't work.
Also, Stillwell said that no weapon could kill him. Some fans argue that she could have been exaggerating, but Butcher could have taken into account the possibility that she was lying.
I've also seen many realistic arguments explaining why a nuclear bomb should kill him, but we shouldn't forget that this is fiction, and power inconsistencies are common in fictional stories.
Personally, I think he would survive a nuclear explosion, but he would be seriously injured.
There's also the scene where Soldier Boy traps Homelander inside the enriched uranium chamber. There are three storage racks visible, which suggests there was much more enriched uranium than what would be required for a single nuclear bomb.