Cook the egg noodles according to package instructions. Drain and set aside.
In a large skillet or wok, heat the vegetable oil over medium-high heat. Add the minced garlic and sauté for about 30 seconds until fragrant.
Add the bell pepper, broccoli, carrots, and snap peas to the skillet. Stir-fry the vegetables for about 5-7 minutes until they are tender-crisp.
Add the cooked noodles to the skillet along with the soy sauce, oyster sauce, sesame oil, and sugar. Toss everything together until the noodles are well coated and heated through, about 2-3 minutes.
Remove from heat and stir in the sliced green onions. Serve hot, garnished with sesame seeds if desired.