Slice chicken breast halves into thin strips, and then cut strips into 1-inch pieces. Set aside.
Slice mushrooms. Chop green onions (including green tops). Set aside.
Heat 1/2 tablespoon oil in 12-inch skillet over medium-high heat. Add chicken and 1/2 tablespoon Chinese 5-Spice Seasoning; sauté for 3 minutes. Add sliced mushrooms, sun-dried tomatoes, and remaining 1/2 tablespoon Chinese 5-Spice Seasoning; sauté for an additional 3 minutes. Mix in green onions and remaining oil and cook just until heated through (approximately 30 seconds). Serve immediately, over rice.