Just played Loomian Legacy and noticed how their chat is much larger than the one you normally see
Chat in Loomian Legacy:
Default Roblox chat:
I tried configuring my chat window, but it doesn’t reach equal size to theirs.
Did also notice that the 
report abuse button as well as the 
send icon for the inputbar are missing.
I can’t access the CoreGui to alter these things. Any way to alter the chat like that?
There should be a service named “TextChatService” in your explorer tab
And it has ChatWindowConfiguration as its child and you can adjust property WidthScale of it
It appears to go until 2, yea
Yet in practice it’s capped at 1.1 for some odd reason. If I change it to 1.5 it still results in the same Width as 1.1
You have to make sure the numbers are both the same or similar, I think.
By the way if this does help you, make sure to mark @minus10degrees answer as the solution.
Increasing the HeightScale to match with the WidthScale didn’t affect the width
