#The venn diagram of what a noun is and what a pronoun is has very little non-overlapping space that can't be explained

[endormiscat]

Well yeah but you know what also can be a stand in for nouns? Other nouns. "Me" and "you" are uniquely special in that as active participants you can address them. But you can't address just about any pronoun, which means that being an address term is a grammatical role that can't be filled by a pronoun doing exclusively pronoun things.

"Chat" is a noun, just like "dude", " fellas", and "gang"; and thus can do anything a noun can do, which also looks a lot like what a pronoun does, which is what is tripping people up. But standing in for nouns is not the only thing a pronoun can do. They have special properties that "chat" lacks.