To call the moderation on Stack Exchange Chat inconsistent would be somewhat of an understatement. A flagged message might be handled by any of the 300+ moderators, the result is highly variable.
While there is a rather fuzzy line between acceptable and inacceptable behaviour in chat, in most cases it is reasonably clear whether a message should be removed. But there is a much greater uncertainty about what the appropriate suspension length is. Depending on who handles a flag, the result might be anything from the standard 30-60 minutes auto-suspension and a few weeks.
Unlike for suspensions on the main sites, there are no official guidelines from SE regarding suspension lengths in chat. This leads to wildly inconsistent moderator actions by different moderators for similar offenses.
An additional issue with this situation is that in my personal opinion the manual suspension lengths are often too short. They are usually measured in hours or a few days. Of course chat is a different medium than the main sites, but I think that even for a faster medium like chat a suspension length of a day or two is not all that useful.
The short (30-60 min) auto-suspension with a spam/offensive flag deals with immediate issues and lets the whole thing calm down a bit. That is enough for most situations. If that isn't enough, I would directly go to suspension lengths similar to the main sites, though a bit toned down. Something more like 3,7,30, ... days.
Manual suspensions are much rarer than the automated ones in chat, and usually deal with users that were repeatedly flagged or committed especially serious first offenses. The recent addition of annotations to chat users and recording of previous suspension now makes it possible to make chat moderation more consistent and to deal better with repeated low-level offenses.