1 cup canned tomato sauce
½ cup ketchup
3 tablespoons brown sugar
2-½ tablespoons apple cider vinegar
2 teaspoons garlic powder
¼ teaspoon crushed red pepper
1-½ pounds boneless and skinless chicken breasts, sliced in strips

Place tomato sauce, ketchup, brown sugar, vinegar, garlic powder, and crushed red pepper in a crock-pot. Stir until mixed. Add chicken and coat well with the sauce. Cover and cook for 3 to 3 ½ hours on high or 7 hours on low, or until fully cooked.