01 - Place chicken thighs in a single layer at the bottom of the slow cooker.
02 - Whisk together basil pesto, ranch seasoning, chicken broth, heavy cream, and Parmesan cheese in a medium bowl until thoroughly combined.
03 - Pour sauce evenly over chicken, cover, and cook on LOW heat for 4 to 6 hours until chicken reaches internal temperature of 165°F.
04 - Transfer chicken to serving platter, spoon sauce over top, and garnish with fresh basil and extra Parmesan cheese.