Prepare quinoa according to packet instructions.

In a medium bowl, whisk together butter, lemon juice, garlic and Italian seasoning. Season to taste with pepper. Place diced chicken in the same bowl and toss to evenly coat.

Heat a large non-stick skillet over medium-high heat. Spray with oil. Add the chicken in an even layer and cook undisturbed for 4 minutes. Flip and cook for an additional 3 minutes until the chicken is cooked through. Remove chicken to a plate and set aside.

In the same skillet, spray again with oil and reduce to medium heat. Add the peppers and onions. Season with pepper and sauté for 10 minutes or until tender, stirring occasionally. Then add chicken and remaining juices back into the skillet, gently stir to combine and reheat the chicken. Divide the chicken and vegetables between two plates and serve.