It looks like VGChartz forum api is blocking Chrome's Spell Check.

(I have tested other forums this issue only applies to VGChartz)

What does not work:
Anything that uses rich text including:
Creating a new thread
Quoting a thread
Editing a thread
Using the reply button

What does work:
Replying to a thread after scrolling to the bottom. (Doesn't use rich text)

I am not having these issue on any other sites.  

I thought it never supported spell check. Good luck, non-native speakers!

EDIT: 7000th post!

On Firefox, the spell check seems to work on "Quick Reply" but on "Rich Text Reply," it doesn't seem to want to work at all

Spell Check is not working on anything that uses the rich text interface on Chrome as well. Good catch! Updated OP as a result. 

Get to work ioi, and while you're at it, update to use the new html embed code too.

Yeah, it's rough for those of us born without the ability to spell worth a damn lol.

We don't need luck, we only need Google translator.

Gimme dat spell check! I typed this in the Quick Reply box (Firefox), and it is working (i.e. Firefox said, "Wtf does 'dat' mean...?").

I am editing this post, and while editing Firefox no longer finds that "dat" isn't a word. Firefox is entirely comfortable with "dat" in the Edit Post mode.

I tried pressing the "Reply" button to this post, and in Reply mode Firefox does not think there is anything wrong with "dat".

Finally, I tried pressing the "Quote" button, and in Quote mode Firefox does not think there is anything wrong with "dat".

Dat Rich Text spellcheck...

Same problem over here. Though I don't really mind the stupid spell check function keeps changing my words 😬😬!

I grammer gud!