Prepare the chicken by dicing it into bite-sized pieces, then cook in a skillet with vegetable oil for 5-7 minutes until cooked through.
Cook the vermicelli noodles according to package instructions, then drain and rinse under cold water.
Prepare the vegetables by slicing the bell peppers, cutting the broccoli into florets, and rinsing the snap peas. Stir-fry the garlic and vegetables for 3-4 minutes.
Combine the cooked chicken, vermicelli noodles, soy sauce, oyster sauce, sesame oil, and ground ginger in the skillet. Cook for an additional 2-3 minutes until heated through.
Stir in the sliced green onions and adjust seasoning with salt and pepper before serving.