Season the chicken breasts generously with salt, pepper, and half the oregano on both sides. Heat 1 tablespoon of olive oil in a large skillet or Dutch oven over medium-high heat until shimmering. Cook the chicken for 6-7 minutes per side until golden brown and the internal temperature reaches 165°F on a meat thermometer. Remove to a plate and tent loosely with foil to rest.

In the same pan with all those flavorful browned bits, add the remaining tablespoon of olive oil. Add the chopped red onion and cook for 2-3 minutes, stirring occasionally, until softened and translucent. Add the minced garlic and cook for just 30 seconds until fragrant but not browned.

Add the diced bell pepper and zucchini to the pan, cooking for 3-4 minutes while stirring occasionally until they begin to soften but still have some crunch. Stir in the orzo pasta, coating it well with the oil and vegetables for about 1 minute.

Pour in the chicken broth and bring to a boil over high heat. Once boiling, reduce heat to medium-low, cover with a lid, and simmer for 10-12 minutes, stirring every few minutes to prevent sticking. The orzo should be tender and most of the liquid absorbed.

While the orzo cooks, slice the rested chicken into strips. Once the orzo is done, add the cherry tomatoes, balsamic vinegar, and remaining oregano to the pan. Gently fold in the sliced chicken and cook uncovered for 2-3 minutes until the tomatoes are warmed through and the balsamic creates a glossy glaze. Remove from heat, garnish with fresh torn basil leaves, and serve immediately.