Dice the chicken breast into small, even cubes and season with sea salt and black pepper.
Heat the avocado oil in a large skillet or wok over medium-high heat until shimmering.
Add the chicken to the pan and sear for 5-6 minutes, stirring occasionally, until golden brown and cooked through.
Remove the chicken from the pan and set aside on a plate.
In the same pan, add the toasted sesame oil along with the minced garlic, grated ginger, and frozen peas and carrots.
Sauté the vegetables for 2-3 minutes until the aromatics are fragrant and the peas are tender.
Push the vegetable mixture to one side of the pan and crack the egg into the empty space, scrambling until fully set.
Add the chilled brown rice and the cooked chicken back into the pan, breaking up any rice clumps with a spatula.
Drizzle the tamari over the rice and stir-fry everything together for 3-4 minutes until the rice is heated through and slightly crispy.
Garnish with thinly sliced green onions and serve immediately.