In a medium bowl whisk together chicken broth, hoisin sauce, oyster sauce, sherry, sugar, soy sauce and crushed red pepper flakes. Set aside.
Toss chicken with cornstarch in a bag until all of the strips are thoroughly coated. Heat a deep fryer to 375 degrees. Fry chicken strips in batches until golden brown and fully cooked. Drain on paper towels. Place into the oven to keep warm.
Add a tablespoon or two of oil to a wok over medium-high heat. Add garlic, onion and green onions. Season vegetables with salt and pepper. Stir fry until added vegetables have reached your desired tenderness. Remove from pan and set aside.
Pour the sauce mixture into the wok and cook until the sauce becomes thickened and bubbly. Add chicken strips into a large serving bowl, pour sauce over chicken, add onions and mix well. Serve with white rice.