Dice the chicken breast into small, bite-sized pieces and season evenly with sea salt and black pepper.
Heat the toasted sesame oil in a large skillet or wok over medium-high heat until shimmering.
Add the chicken to the pan and sauté until golden brown and cooked through, approximately 5 to 6 minutes.
Stir in the minced garlic, grated ginger, and diced carrots, cooking for another 2 minutes until the vegetables begin to soften.
Add the frozen peas to the skillet and toss for 1 minute until they are bright green and thawed.
Push the chicken and vegetable mixture to the outer edges of the pan and crack the egg into the center.
Gently scramble the egg until it is fully set, then fold it into the rest of the ingredients.
Add the chilled cooked brown rice and tamari to the skillet, stirring constantly for 2 to 3 minutes to ensure the rice is heated through and well-coated.
Remove from heat and garnish with thinly sliced green onions before serving.