Heat 1 teaspoon of olive oil in a large nonstick saucepan set over medium-high heat.
Add the chicken, ⅛ teaspoon salt and ¼ teaspoon pepper, and cook until the chicken is barely cooked through (it will cook further later). Transfer to a plate.
Heat the remaining 1 teaspoon of olive oil in the same saucepan, and add the onions, carrots, oregano, crushed red pepper, ¼ teaspoon pepper and ⅛ teaspoon salt. Cook until the vegetable are starting to soften, about 5 minutes.
Add the garlic and cook for 1 minute.
Stir in the chicken broth and diced tomatoes, bring to a boil, then lower the heat to a simmer.
Cook for 15 minutes, adding the green beans and chicken halfway through the cooking.
Add the tortellini and cook until it is just tender (5 minutes for fresh and 8 minutes for frozen).
Stir in the parsley. Season with salt and pepper, to taste. Serve.