Label a gallon freezer bag with the recipe name, date and reminder to add broth after thawing. Put raw chicken, drained lentils, sweet potato, onion, garlic, ginger, tomatoes, cumin and salt inside; press out excess air and seal.
Freeze the bag flat on a tray immediately, then store for up to 3 months for best quality. Keep broth, peanut butter and lime juice separate from the raw bag.
Move the bag to a rimmed dish in the refrigerator for 24 to 48 hours until completely thawed, keeping it at 40°F or below. Empty the entire bag into a 6-quart slow cooker and add the measured broth; do not start with frozen chicken.
Cover and cook on low for 6 to 7 hours until chicken reaches 165°F, lentils have softened and sweet potato breaks easily under a spoon.
Lift chicken onto a board and shred into short pieces. Whisk peanut butter with a ladleful of hot broth in a bowl until smooth, then stir it and the chicken back into the cooker.
Cook on high for 15 minutes until evenly hot, then stir in lime juice. Divide among six servings.
For cooked freezer portions, cool the stew promptly in shallow containers, refrigerate within 2 hours and chill completely before covering and freezing for up to 3 months.
Reheat one cooked frozen portion in a small covered saucepan with its measured reheating water over low heat, stirring and breaking it apart as it softens. Simmer until the whole portion reaches 165°F, usually 20 to 30 minutes.