Hello! Let's clarify the key difference between nicht and kein in German negation.
Kein negates nouns, meaning "no" or "not a." For example, "Ich habe ein Auto" becomes "Ich habe kein Auto" (no car).
Nicht negates verbs, adjectives, adverbs, and nouns with definite articles. For instance, "Ich spreche nicht Deutsch" (I don't speak German).
Remember: kein for nouns, nicht for everything else. Your German negation will be clear!