Choose a freezer-safe zip-top bag sized for your chicken and label it with the date and contents using a marker.
If you have two pieces of chicken or fewer, place them in the bag, press out as much air as possible, seal the bag, and put it in the freezer.
If you have more than two pieces, arrange the pieces in a single layer on a parchment-lined baking sheet so they do not touch, then freeze until solid (about 4 hours).
When frozen solid, quickly transfer the pieces into the labeled freezer bag, remove excess air, seal, and return the bag to the freezer.