01 - Cook chow mein noodles according to package directions until al dente. Drain thoroughly and rinse under cold running water to stop cooking and prevent sticking. Pat dry with paper towels to remove excess moisture for optimal crisping.
02 - Heat 1 tablespoon vegetable oil in a large nonstick skillet or wok over medium-high heat until shimmering. Spread cooked noodles in an even layer. Fry undisturbed for 4 to 5 minutes until deep golden brown and crispy on bottom. Carefully flip and crisp second side for 2 to 3 minutes. Transfer to a plate and set aside.
03 - Whisk together soy sauce, oyster sauce, hoisin sauce, sesame oil, sugar, minced garlic, grated ginger, water, and cornstarch in a small bowl until cornstarch is completely dissolved and mixture is smooth. Set aside near stove.
04 - Wipe skillet clean if needed. Heat remaining 1 tablespoon oil over high heat. Add onion slices and julienned carrot; stir-fry for 2 minutes until onion begins to soften. Add bell pepper, mushrooms, and snow peas; stir-fry for 3 to 4 minutes until vegetables are tender-crisp and vibrant in color.
05 - Pour prepared sauce over vegetables, stirring constantly for 1 minute until sauce thickens and coats all vegetables. Add bean sprouts and half the spring onions; toss gently to combine and heat through, about 30 seconds.
06 - Arrange crispy noodles on a serving platter. Top with sauced stir-fried vegetables. Garnish with remaining spring onions, toasted sesame seeds, and fresh coriander leaves. Serve immediately while noodles remain crispy.