Season the chicken with 3/4 tsp. of salt and 1/4 tsp. of black pepper. Brush 1/4 cup of the pesto over both sides of the chicken and let it marinate for about 15 minutes.

In a large skillet, heat 2 tablespoons of olive oil over medium heat. Arrange the chicken in the pan, and cook undisturbed for about 5 minutes, or until golden. Flip the chicken and cook for another 2 minutes. Transfer the chicken to a plate.

In the same pan, add the chopped onion and cook for about 3 minutes until softened. Stir in the crushed red pepper flakes and orzo, cooking for an additional 1 to 2 minutes. Add the broth, remaining 1/4 cup of pesto, 1/2 tsp. salt, and 1/4 tsp. black pepper. Bring to a boil and nestle the chicken back into the pan, topping with Parmigiano-Reggiano cheese. Cover and simmer for about 15 minutes, or until orzo is al dente.

Combine the halved cherry tomatoes, chopped basil, minced garlic, and remaining 2 tablespoons of olive oil in a medium bowl, seasoning with a pinch of salt.

Once the orzo is cooked, spoon the tomato-basil mixture over the chicken and orzo. Add extra Parmigiano-Reggiano on top if desired before serving.