Dice the chicken breast into small 1-inch pieces 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 until golden brown and cooked through, about 5-6 minutes.
Stir in the minced garlic and grated fresh ginger, cooking for 30 seconds until the aromatics are fragrant.
Add the frozen peas, frozen carrots, and cooked brown rice to the skillet, stirring to break up any clumps.
Push the chicken and rice mixture to the edges of the pan and crack the egg into the center.
Scramble the egg until fully set, then toss everything together to combine the ingredients.
Drizzle the tamari and toasted sesame oil over the mixture, stirring well to coat every grain of rice.
Garnish the dish with thinly sliced green onion and sesame seeds before serving warm.