Season the chicken breasts on both sides with salt, pepper, and half of the oregano. Heat 1 tablespoon of olive oil in a large skillet or Dutch oven over medium-high heat. Add the chicken and cook for 6 to 7 minutes per side until golden brown with an internal temperature of 165°F. Remove from pan and set aside to rest.

In the same pan, add the remaining tablespoon of olive oil over medium heat. Add the chopped red onion and cook for 2 to 3 minutes until softened. Add the minced garlic and cook for another 30 seconds until fragrant.

Add the diced bell pepper and zucchini to the pan, stirring to combine. Cook for 3 to 4 minutes until the vegetables begin to soften. Pour in the orzo pasta and stir well to coat with the oil and vegetables.

Pour in the chicken broth and bring to a boil over medium-high heat. Once boiling, reduce heat to medium-low, cover, and simmer for 10 to 12 minutes, stirring occasionally, until the orzo is tender and has absorbed most of the liquid. Add more broth if needed.

While the orzo cooks, slice the rested chicken into strips about 1/2 inch thick. Add the halved cherry tomatoes, balsamic vinegar, and remaining oregano to the pan with the orzo. Gently fold in the sliced chicken and cook uncovered for 2 to 3 minutes until the tomatoes are warmed through and the balsamic creates a light glaze.

Remove from heat and taste, adjusting salt and pepper if needed. Garnish with fresh torn basil leaves and serve immediately while hot.