In a small bowl, whisk together the cornstarch, reduced-sodium soy sauce, toasted sesame oil, oyster sauce, chicken broth, and light brown sugar until smooth. Set aside.
Heat a wok or large skillet over medium-high heat. Add a tablespoon of toasted sesame oil. Once hot, add the minced garlic and ginger paste, sautéing for about 30 seconds until fragrant.
Add the sliced yellow onion to the pan. Stir-fry for 2-3 minutes until the onion becomes translucent. Then, toss in the frozen sugar snap pea stir-fry vegetables. Stir everything together and cook for another 5 minutes until the vegetables are heated through.
Stir in the shredded or sliced rotisserie chicken. Cook for an additional 2 minutes, allowing the chicken to warm up and absorb the flavors.
Pour the prepared sauce over the stir-fry mixture. Stir well to combine, ensuring the sauce coats all the ingredients. Cook for about 2-3 minutes until the sauce thickens slightly.
Remove from heat and transfer to serving plates. Top with sliced green onions, sesame seeds, and a drizzle of sriracha if desired. Enjoy your Rotisserie Chicken Stir-Fry warm!