Begin by bringing a pot of water to a rolling boil. Add the chow mein egg noodles, allowing them to soak for 30 seconds to 1 minute until they soften but remain slightly firm. Once done, drain the noodles and set them aside.

In a bowl, whisk together the dark soy sauce, regular soy sauce, oyster sauce, fish sauce, granulated sugar, and water until the sugar completely dissolves, creating a smooth sauce.

Heat 1 tablespoon of corn oil in a hot wok over medium-high heat. Add the diced yellow onion along with the whites of the green onions. Sauté for about 1 minute until the onions become translucent and fragrant.

Return the wok to high heat and add another tablespoon of corn oil. Carefully lay the drained chow mein noodles in a thin layer across the wok's surface. Cook for about 2 minutes until the bottom is golden and crispy.

Once the noodles are crispy, add the sautéed aromatics, bean sprouts, and the prepared sauce. Gently toss everything together for 1-2 minutes, ensuring the noodles are well-coated and the vegetables are heated through. Finish by stirring in the sesame oil.