Nominally he's in the bottom class (4)
I believe the answer is:
otto
'nominally he's' is the definition.
The definition suggests a singular noun which matches the answer.
'in the bottom class' is the wordplay.
'in' indicates the answer is hidden within the clue.
'OTTO' is hidden within 'bottom class'.
Can you help me to learn more?
(Other definitions for otto that I've seen before include "perfume maker" , "Four-stroke cycle -- palindromic name" , "Producer of engines" , "He's a German, whichever way you look at it" , "Ger. name (palindrome)" .)