Place the chicken breasts in a large resealable freezer bag.
Add the pesto sauce, diced zucchini, diced carrots, corn, chicken broth, and dry Ranch seasoning. If you're adding Brussels sprouts, toss them in as well.
Cook in the Crock-Pot on low for 4-6 hours.
Remove the bag from the freezer to thaw.
Lay everything out on a baking sheet lined with aluminum foil.