First, prep your sandwich bags by stretching them into and over a normal-sized glass. Then, defrost and cut your chicken as if you were about to cook it. Just put it in the glass, instead. Fill it up with one serving, two, or however many you think you’ll cook at a given time.
Clean up your cutting space and wash your hands well. Then, take each bag and press it flat and zip it up to get most of the air out. Stack and freeze.
Now, when you want to whip up a quick chicken dish, just grab a bag and go!