Would it be acceptable to chew mirtazapine tablets?

Probably: I am not aware of a specific prohibition of it. I assume you are talking about the real tablets and not the soltabs that are dissolving. In any case, I am thinking that it should be fine although i would not assume that you should do this for all your medications. Also, it may not taste very good if you do it this way as well!

May not be advised : Most medications are meant to be taken as directed. The mechanism behind the release , metabolism and blood level of the drug can depend on its design which can include the coating and form among other things . For some medications cutting, crushing or chewing can destroy the active drug and for others it may cause too rapid & too high blood levels.Please check with your doc &/or pharmacist.