Begin by dicing the chicken breasts into bite-sized pieces. Season with salt, pepper, oregano, and basil.
In a large pot, bring salted water to a boil. Add the orzo and cook according to package instructions until al dente (about 7-8 minutes). Drain and set aside.
While the orzo is cooking, heat olive oil in a skillet over medium-high heat. Add the diced chicken and cook until browned and cooked through, about 5-7 minutes. Remove the chicken from the skillet and set aside.
In the same skillet, reduce heat to medium and add the onion. Sauté until translucent, about 3-4 minutes. Add the minced garlic and cook for an additional minute.
Stir in the chicken broth, cherry tomatoes, and fresh spinach. Cook until the tomatoes are softened and the spinach is wilted, about 3-4 minutes.
Return the cooked chicken to the skillet and mix well. Add the cooked orzo to the skillet and stir to combine all ingredients. Cook for an additional 2-3 minutes to heat through.
Remove from heat and, if desired, sprinkle with grated Parmesan cheese before serving.