Drain the pineapple juice into a small bowl. Set the drained can of pineapple to the side. Add the chicken stock, brown sugar, soy sauce and minced garlic to the bowl with the pineapple juice.
Place the chicken breasts in the base of the slow cooker and pour the pineapple chunks around the chicken. Season with salt and pepper. Pour the pineapple-soy sauce mixture over the top.
Set on low and cook for 8 hours. With 30 minutes, left in the cooking cycle, swirl the cornstarch with a few Tbsp of water and stir it into the sauce. Cook for 30 more minutes to allow sauce to thicken.
Cook the rice as directed.
Prepare veggies or salad.
Serve Slow Cooker Pineapple Chicken with sesame seed garnish over rice with veggies or salad.