Pat the chicken breast dry and dice into bite-sized pieces, then season evenly with sea salt, black pepper, garlic powder, and ground ginger.
Heat the avocado oil in a large non-stick skillet or wok over medium-high heat until shimmering.
Add the seasoned chicken to the skillet in a single layer and sear until golden brown and cooked through, approximately 5 to 7 minutes.
Remove the cooked chicken from the pan and set it aside on a plate; lower the heat to medium and add the toasted sesame oil.
Toss in the frozen peas and carrots, sautéing for 2 to 3 minutes until they are vibrant and tender-crisp.
Add the chilled cooked brown rice to the skillet, breaking up any clumps with a spatula, and drizzle with tamari.
Press the rice down firmly into the pan and let it sit undisturbed for 2 minutes to develop a delicious, crispy texture.
Return the chicken to the pan, add the sliced green onions, and toss everything together until well combined and heated through.
Garnish the dish with toasted sesame seeds and serve immediately while the rice is perfectly crackling.