In a medium bowl, whisk together peanut butter, soy sauce, honey, rice vinegar, sesame oil, minced garlic, grated ginger, and red pepper flakes until smooth. Gradually whisk in the chicken broth until fully combined.
Place the chicken breasts in the slow cooker. Pour the peanut sauce mixture over the chicken, ensuring it's evenly coated.
Cover and cook on low for 3-4 hours, or on high for 1.5-2 hours, until the chicken is cooked through and tender.
Remove the chicken from the slow cooker and shred it using two forks. Return the shredded chicken to the sauce and stir to combine.
Serve the Thai peanut chicken over cooked rice. Garnish with chopped peanuts, cilantro, and lime wedges, if desired.
Notes
This recipe can be adjusted to your spice preference by adding more or less red pepper flakes. For a thicker sauce, you can mix 1 tablespoon of cornstarch with 2 tablespoons of water and stir it into the sauce during the last 30 minutes of cooking.