A Shih Tzu loves to chew like any other dog breed. Chewing is not just consuming food, it can be a trait born from teething and has a variety of reasons. So when he is chewing your clothes or furniture, make sure to curb that habit safely.
It is an exploring part of your Shih Tzu, so you have to provide him with alternatives to make him less harmful to your belongings.
Identifying why your Shih Tzu wants to chew everything can make an easier solution. A reason why he is chewing everything maybe when you leave him alone at home and he becomes anxious.
Play with your Shih Tzu before leaving home. Rub treats in your hands to leave the scent there. Leave home normally. Start leaving home with shorter periods and extend it gradually.
Shih Tzus can become bored just like humans. Chewing may be a result of that. Provide entertainment for him to give alternatives. Exercises, playtime, chew-proof toys, and more.
You should look for chew-proof toys like rawhide, rubber toys, nylabones, and more. Keep all your valuable things away from your Shih Tzu.