Rinse the chicken thighs and pat them dry.
In a large bowl or gallon-size Ziploc bag, combine all ingredients except for the chicken. Mix thoroughly.
Set aside ½ cup of the sauce mixture for serving later.
Add the chicken thighs to the remaining marinade, ensuring they are well coated. Seal and refrigerate for at least 4 hours or overnight.
Preheat the grill to medium-high heat (around 400°F).
Lightly brush the grates with oil to prevent sticking.
Place the marinated chicken on the grill and cook for about 10 minutes without turning or moving.
Flip the chicken and continue cooking until the internal temperature reaches 165°F, approximately another 10 minutes.
While the chicken is cooking, grill the pineapple rings until golden on each side.
Once everything is cooked, remove from the grill.
Brush the reserved marinade over the chicken. Optionally, place the chicken under the broiler for a few minutes to thicken the sauce, or heat the reserved sauce in a saucepan on the stovetop until slightly thickened, then brush it over the chicken.
Garnish with sliced green onions before serving.