Why is there no accusative change here?
You mean Accusative to Genitive? That happens when the verb is negated (and it's not like literally 100% of verbs). "On nie je chleba" would be Genitive, and here's Accusative.
He probably meant that Accusative = Nominative. Most masculine inanimate nouns don't change form in Accusative so Accusative = Nominative.
I mean that "Chleb" does not change, and this is accusative. "Herbata" becomes "herbatę", so shouldn't "chleb" become something else too?
I replied that most masculine inanimate nouns don't change form in Accusative so Accusative = Nominative.
There are inaminate nouns? Doesn't that mean that only people and animals change?
Not only, but nouns naming people and animals have Accusative = Genitive.