The chambers do look bigger now that we see this whole view of it, but still look so temporary somehow, especially, because if I recall, the courthouse itself is very nicely done, nicer than many of us expected for such a small town courthouse, according to comments I remember reading on the video when the interior courtroom was first shown. Compared to the nicer courthouse, the chambers don't look like much, like not much thought went into the decoration or interior design (or lack of it).
I just had a thought. Could it be possible that this chambers we see in the video really is just a temporary room, because his actual chambers are sealed off at the moment, due to having been the scene of the crime in what is still, I believe, an ongoing investigation? That might make sense, but I still doubt it. I think it just looks like their interior design budget was spent mostly on the parts of the courthouse that more people (the public citizens) would see.