Trim fat and extra skin from the chicken thighs place them in a large bowl. Combine all the spice ingredients for the marinade in a small bowl, mix together.
Drizzle 1 tablespoon of olive oil over the chicken thighs, toss to coat. Sprinkle the seasoning mix over the chicken and toss to coat. Refrigerate for at least 1 hour or more.
Add 1 tablespoon of olive oil to dutch oven and heat over medium-high heat. Brown andouille sausage on both sides, transfer to a plate.
Add the chicken thighs to the pan, skin side down, and sear for 2-3 minutes per side until crispy and browned. Transfer chicken to the plate with the sausage.
Lower heat to medium and add the onion, green pepper, and celery. Saute for about 2-3 minutes, until softened. Add the minced garlic and saute another minute.
Add rice, chicken stock, Cajun seasoning, salt, and pepper. Stir, and bring to a simmer.
Place the chicken thighs and sausage on top of the rice. Cover and simmer for 20-25 minutes until liquid is absorbed, rice is tender, and chicken is cooked through.
Garnish with sliced green onions and minced parsley if desired.