Spray inside of 4-quart slow cooker with cooking spray. Place undrained tomatoes, beans, undrained corn, ranch mix, chili powder and cumin in slow cooker; stir to combine. Add chicken and cover with tomato mixture. Cover and cook on HIGH 4 hours or LOW 6 hours, until chicken is tender.
Pull chicken into shreds with 2 forks. Cut cream cheese into 8 pieces; stir into chili until melted and combined. Top each serving with cilantro and avocado, if desired.
