Place the chopped chicken, peppers, green onions, and water chestnuts in a large resealable freezer bag. Pour the bottle of kung pao sauce over everything.
Remove excess air, seal, and freeze.
Slow cooker instructions:
Thaw.
Place everything from the bag into the Crock-Pot.
Cook on low for 3-5 hours.
Serve over rice.
If desired, sprinkle some peanuts on top.
Skillet cooking instructions:
Thaw.
Dump everything from the freezer bag into a skillet.
Cook over medium-high heat until chicken is thoroughly cooked through and the sauce has thickened slightly.
Serve over rice.
Sprinkle some peanuts on top if you like.
Notes
Pro tip: If you want to make assembling this much faster, you can put the chicken breasts into the freezer bag whole and then cube them on the day of cooking either before or after cooking. This way is messier, but if you're wanting to assemble a lot of freezer meals at once and just going for speed, that is an option.