Heat a large skillet or wok over medium-high heat with half of the toasted sesame oil.
Add the diced chicken breast, sea salt, and black pepper, cooking until the chicken is golden and cooked through.
Push the chicken to the outer edges of the pan and add the remaining sesame oil, minced garlic, and grated ginger to the center.
Sauté the aromatics for 30 seconds, then stir in the frozen peas and carrots along with the white parts of the sliced green onions.
Add the chilled brown rice to the pan, breaking up any large clumps with a spatula, and toss everything together to combine.
Create a small well in the center of the mixture, crack the egg into it, and scramble until just set before folding it into the rice.
Drizzle the tamari over the dish, toss one final time to coat, and garnish with the green tops of the onions before serving.