01 - Arrange chicken thighs in a single layer at the bottom of the slow cooker.
02 - In a medium bowl, whisk together pesto, ranch seasoning, chicken broth, heavy cream, and Parmesan cheese until fully combined.
03 - Pour the sauce mixture evenly over the chicken thighs.
04 - Cover and cook on LOW setting for 4-6 hours, or until chicken reaches internal temperature of 165°F and is tender throughout.
05 - Transfer chicken to a serving platter, spoon sauce over top, and garnish with fresh basil and additional Parmesan if desired.