Does Okun's law also work for nominal (not real) GDP growth?
Does Okun's law work at all?
It was an empirical observation of the relationship between unemployment and an estimate of the "output gap" (the relative difference between actual GDP and potential GDP)
To the extent that the relative difference between actual GDP and potential GDP may be the same whether calculated using nominal GDP or real GDP, then the relationship should hold either in both cases or in neither. Otherwise the argument becomes one of saying that the output gap is affected by inflation