I don't know what is going on with Nate Cohn.

It isn't clear it is a different model.

And FiveThirtyEight has explained a lot about the model, Nate just seems to refuse to listen to what they say.

The FiveThirtyEight model is a multivariate model that uses state correlations, so you can't do the sort of reverse engineering that Nate attempts in this thread.

It is why you can get sort of counterintuitive results with some of the states as the model uses some information from the polling of similar states to add richness- e.g. if Harris is doing really well in Michigan it informs Wisconsin. Likewise national polling informs state polling.

Harris' fundamentals are different than Biden's as well. She has different approval ratings. She's not the incumbent.