true, I never thought of it that way on the other hand they talk about people in Washington maybe being alive with Nukes that would be ruled out I suppose.

Maybe they did When the team climb out of the facility at the end of the movie, it looks like a missile silo minus the missile.

True that, the eye-patch scientist in Dawn suggested that the government do just thatat least to major cities, as that's where most of the zombies congregated.

There's nothing in the film to prove one way or the other that the government
didn't
try using nukes.

This used to be a signature

I don't really see the benefit to nuking targets. Failing a counter-virus that deactivates the undead and doesn't affect the living, the only real option is mass armament and training of survivors, probably with 22lr rifles, to go around popping heads.
But in Romero's universe, and probably the most likely outcome, the government is too slow to act and civilians are too molly-coddled to do what they need to do.

It would be the equivalent of cutting off your own cock.