Place the cubed chicken and julienned red bell pepper into the slow cooker insert.
In a medium mixing bowl, whisk the peanut butter, soy sauce, honey, lime juice, ginger, garlic, red pepper flakes, and chicken broth until the emulsion is smooth.
Pour the liquid mixture over the chicken and peppers, stirring to ensure all surfaces are coated.
Secure the lid and cook on High for 3 to 4 hours or on Low for 6 to 8 hours until the internal temperature of the chicken reaches 165°F (74°C).
Stir the contents thoroughly to re-incorporate the sauce before serving.
Garnish with chopped peanuts and green onions prior to service.