Nebel studied philosophy and classical philology in Freiburg, Marburg and Heidelberg from 1923 to 1927, under Martin Heidegger and Karl Jaspers.
Nebel was drafted into the Luftwaffe and worked as a translator in Paris in 1941, where he met Ernst Jünger.
After comparing fighter airplanes with insects in an essay, he was demoted and transferred as a construction soldier to Alderney.
He published his diaries, and the essay collections Von den Elementen and Tyrannis und Freiheit.
Nebel switched his ideological alignment several times during his life; he identified as a Social Democrat, a Marxist, a Nihilist, an Atheist, a Reactionary and after World War 2 he developed his own idiosyncratic form of conservativism.