Not sure I like the idea of compressed monitors, but you CAN do it by switching the direct out take-off point to post compressor. (press sel on an input channel, choose the routing tab and the direct out tab and pull up the “DIR OUT SRC” tab).
BUT that is a global setting, you so you would be post compressor for ALL you direct out aviom feeds, which is almost certainly NOT what you want.
The only other way is to use an aux specifically for the bass monitor feed and route that to an aviom channel, but since mix outputs are usually a scarce resource that may not be an option either. However it would allow you to use different EQ and comp settings to what you are using FOH.