Melt the butter. Combine it with the chicken broth and cream of chicken soup in a freezer safe bag or canister. Zip and knead to mix.
Cut the chicken breasts into strips and dice the onion. Toss them in the sauce bag. Zip and shake to marinate.
Make a note on your label you'll need either homemade biscuit dough or a can of refrigerated biscuit dough when you make this recipe.
Lay the package flat, label and freeze for up to 8 weeks.