Stir-fry chicken in 1 to 2 tablespoons hot oil in wok or large skillet until no longer pink. Drain excess fat. Cover with 1 bottle Tuscan herb sauce by Knorr and simmer 10 to 15 minutes. In a separate wok or skillet, stir-fry onions and peppers in 1 tablespoon hot oil for 3 to 4 minutes, until still crisp. Add chicken and sauce to onions and peppers, simmer together a few minutes to blend flavors. Serve over fettuccini or other cooked noodles.