In a mixing bowl, stir together the chicken broth, cream of chicken soup, garlic powder, salt, and black pepper until smooth.
Pour the rice into the bottom of the slow cooker and spread it into an even layer.
Add the mixed vegetables on top of the rice.
Place the chicken breasts over the vegetables.
Pour the broth mixture evenly over the chicken and vegetables.
Cover and cook on low until the rice is tender and the chicken reaches 165°F internally.
Remove the chicken, shred or cut it into bite-size pieces, and stir it back into the rice mixture.