Their valet service helped smooth the transition to the school day from what for many kids was a raucous home environment
What kind of function is the italicized part in the sentence above? it is a Noun clause or Adverbial Clause?
from what for many kids was a raucous home environment
is neither a noun clause nor an adverbial clause; it is a preposition phrase.
The what-clause embedded in this preposition phrase is the noun clause you probably want to ask about. This is the object of preposition from.