If you’re making your own cajun seasoning, combine all ingredients in a small bowl until fully combined. Season the chicken breasts with 1 tablespoon cajun seasoning. Make sure all sides are coated. In a skillet, heat 2 tablespoons vegetable oil. Once heated, add the chicken and cook over medium heat for 4-5 minutes. Flip the chicken then cook for about 3 minutes on the other side or until the chicken is cooked. Remove the chicken from the skillet and set aside.
In the same pan, without cleaning it out, add the bell pepper, onion, garlic and remaining 1 tablespoon of cajun seasoning. Cook for about 2-3 minutes or until the onion begins to turn translucent. You may need to add 1-2 tablespoons of chicken broth to deglaze the pan if your pan dries out too much.
Add orzo and cook until toasted, about 1-2 minutes. Add tomato paste, chicken stock, milk, and an extra pinch of salt to taste. Stir until well combined. Bring to a simmer, cover the skillet, and cook until all of the liquid is absorbed. About 12-15 minutes.
Slice the cooked chicken breasts and add to the orzo. Top with parsley and green onion for garnish. Serve warm.