Cook the rice 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 sliced onion, and sauté for about 2 minutes until fragrant.
Add the bell pepper, broccoli, and snap peas to the skillet. Stir-fry for 3-4 minutes until the vegetables are tender but still crisp.
Add the cooked chicken (or tofu) to the skillet and stir to combine.
In a small bowl, mix together the soy sauce, oyster sauce, fish sauce, chili paste, and sugar. Pour this sauce over the stir-fried vegetables and protein, stirring well to coat everything evenly.
Add the cooked rice noodles to the skillet and toss everything together until the noodles are heated through and well combined with the sauce.
Remove from heat and stir in the lime juice.
Serve hot, garnished with fresh basil leaves and lime wedges on the side.