- Combine soy sauce, hoisin sauce, rice vinegar, sesame oil, garlic, ginger, and black pepper in a small bowl and stir to combine. Reserve ¼ cup for basting.
- Cut the chicken thighs into cubes, remove any excess fat, and add to a shallow bowl along with remaining sauce. Stir to coat chicken.
- Thread chicken cubes onto 6 skewers. Set aside.
- Heat grill to medium-high. Grease grates with cooking oil. Grill chicken kabobs for 12 minutes, turning every 3-4 minutes. Brush with remaining sauce and remove from grill.
- Serve hot, garnished with chopped cashews and green onion.