Step 1: In a medium bowl, whisk together the pineapple juice, soy sauce, brown sugar, ketchup, chicken broth, ginger, garlic, and sesame oil until the sugar is dissolved.
Step 2: Reserve 1/2 cup of the marinade in a separate container and refrigerate; this will be used for basting later.
Step 3: Place the chicken thighs in a large resealable bag or glass container and pour the remaining marinade over them. Ensure all pieces are well-coated. Refrigerate for at least 8 hours, or up to 24 hours.
Step 4: Preheat your grill to medium heat (approx. 350°F/175°C) and lightly oil the grates.
Step 5: Remove the chicken from the marinade (discard the used marinade) and place on the grill. Cook for about 20-25 minutes, turning every 5 minutes (the 'huli' method).
Step 6: During the last 10 minutes of cooking, brush the reserved glaze generously over the chicken every time you turn it until the internal temperature reaches 165°F.
Step 7: Remove from the grill and let the chicken rest for 5 minutes before serving.