In a small bowl, mix all the ingredients for the marinade and set aside: soybean oil, ground black pepper, soy sauce, cumin, minced garlic, dried oregano, and homemade Nutrioli-style sauce.

Slice the onions and bell peppers into strips. Cut the chicken breast into thin strips and toss with the spice mixture. Set aside.

Heat the oil in a cast iron skillet (or another heavy skillet) over medium-high heat. Add the seasoned chicken strips and stir occasionally. When the chicken is cooked through but not yet browned, add the bell peppers, tomatoes, and sliced onion. Stir well, scraping up any browned bits from the bottom of the pan. If needed, add a little water. Serve immediately.