1. 1. Prepare the Chicken: Pat the chicken breasts or thighs dry with paper towels. Cut the chicken into 1-inch bite-sized pieces. This ensures even cooking and makes it easier to eat later.

2. 2. Saute Aromatics: Heat the olive oil in a large skillet or Dutch oven over medium heat. Add the chopped onion and cook until softened and translucent, about 5-7 minutes. Stir in the minced garlic and cook for another minute until fragrant, being careful not to burn it.

3. 3. Brown the Chicken: Add the cut chicken pieces to the skillet with the onions and garlic. Cook, stirring occasionally, until the chicken is lightly browned on all sides. It doesn’t need to be cooked through at this stage.

4. 4. Simmer the Sauce: Pour in the diced tomatoes (undrained), tomato sauce, and chicken broth. Stir in the Italian seasoning, salt, and pepper. Bring the mixture to a gentle simmer, then reduce the heat to low, cover, and let it cook for 15 minutes, allowing the flavors to meld and the chicken to cook through.

5. 5. Add Vegetables: Stir in the frozen mixed vegetables. Continue to simmer, uncovered, for another 5-7 minutes, or until the vegetables are tender-crisp and the sauce has thickened slightly.

6. 6. Cool and Portion: Remove the skillet from the heat and let the chicken mixture cool completely before portioning. This is crucial for food safety and preventing ice crystals in the freezer. Once cooled, divide the mixture into individual or family-sized freezer-safe containers or heavy-duty freezer bags.