In a small bowl, combine the oyster sauce, soy sauce, chicken stock, and cornstarch. Set aside.
Heat a large sauté pan or wok over medium high heat. Add 1 tablespoon of the canola oil. When the oil begins to shimmer, add the chicken and stir fry until just cooked through, about 4 - 5 minutes. Remove from pan to a plate. Drain off any liquid that accumulates before adding the chicken to the stir fry.
Add the remaining oil to the pan and heat to a shimmer. Add the garlic, shallots, ginger, and jalapeno. Quickly sauté for about a minute to just begin to release their flavors. Add the stock mixture to the pan and cook until it begins to thicken, about 2 to 3 minutes. Add the chicken, broccoli, and the scallion and stir just to coat. Serve over the rice noodles.