In a large pot or Dutch oven, heat the olive oil over medium heat. Add the diced chicken and season with salt and pepper. Cook until the chicken is browned and cooked through, about 5-7 minutes.
Remove the chicken from the pot and set aside. In the same pot, add the minced garlic, diced red bell pepper, and halved cherry tomatoes. Sauté for about 3-4 minutes until the vegetables start to soften.
Stir in the orzo pasta and cook for another 2 minutes, allowing it to toast slightly.
Pour in the chicken broth and sprinkle the dried Italian herbs and red pepper flakes (if using). Stir to combine. Bring the mixture to a gentle boil.
Once boiling, reduce the heat to low and cover the pot. Cook for about 10-12 minutes, or until the orzo is tender and has absorbed most of the liquid, stirring occasionally.
Add the cooked chicken back to the pot along with the chopped spinach. Stir until the spinach wilts and everything is heated through. Adjust seasoning with salt and pepper if needed.
Remove from heat and garnish with fresh basil leaves and grated Parmesan cheese if desired.
Notes
Add more vegetables or adjust spices according to your taste.