If your chicken actually needs tenderizing, another approach is to use certain fruits that have enzymes which tenderize meat. Asian pears (the ones that look like apples) and kiwis are the most used, as far as I know. Just peel, core/seed, and grind into a paste or chop medium-fine. Stir with the meat and marinate overnight in the fridge. You can add whatever marinade seasonings you like, of course.
I don't know why chicken needs this, so much, but if you try it with a really tough piece of beef, then cut it into steaks and cook it, you'll see what tenderizing is all about.