Combine chicken, tomatoes, brown sugar and red pepper flakes in freezer bag.

Let all air out of bag.  Seal tight and freeze.

When ready to prepare take it out of freezer and allow to thaw.

Pour chicken and sauce into slow cooker.

Cook in slow cooker on high for 5 hours.

When done cooking shred chicken in sauce.

Serve in flour tortillas with your favorite toppings.