Dr. Pepper Chicken

I decided to try something off the web. It was OK but it needed something, I may try it again and tweak it...

4 boneless, skinless chicken beasts
12 oz can of Dr. Pepper
2 tsp liquid smoke
One envelope dry Lipton onion soup mix
1 Tbsp brown sugar

Place all ingredients in a slow cooker on low for 4-5 hours. If chicken breasts are frozen, cut into pieces when able, about 2 hours in, if thawed, cut sooner. When chicken is done, remove from sauce and whisk in 2 Tbsp cornstarch to thicken sauce, about 30 min. Add chicken pieces to heat through. Serve over rice.