Season the chicken breasts with salt, pepper, and half the oregano. Heat 1 tablespoon of olive oil in a large skillet or Dutch oven over medium-high heat. Cook the chicken for 6-7 minutes per side until golden brown and cooked through (internal temperature of 165°F). Remove chicken and set aside to rest.

In the same pan, add the remaining tablespoon of olive oil. Add the chopped red onion and cook for 2-3 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, cooking for 3-4 minutes until they begin to soften. Pour in the orzo pasta, stirring to coat with the oil and vegetables.

Pour in the chicken broth and bring to a boil. Reduce heat to medium-low, cover, and simmer for 10-12 minutes, stirring occasionally, until the orzo is tender and has absorbed most of the liquid.

Slice the rested chicken into strips. Add the cherry tomatoes, balsamic vinegar, and remaining oregano to the pan. Gently fold in the sliced chicken and cook for 2-3 minutes until the tomatoes are warmed through and the balsamic creates a light glaze.

Remove from heat and garnish with fresh basil leaves. Serve immediately while hot.