Dice the chicken breast into small, bite-sized pieces and season with sea salt and black pepper.
Heat a large skillet or wok over medium-high heat and add half of the sesame oil.
Cook the chicken until golden brown and cooked through, then remove from the pan and set aside.
Add the remaining sesame oil to the pan, followed by the diced carrots, minced garlic, and grated ginger, sautéing until fragrant.
Push the vegetables to the side, crack the egg into the pan, and scramble until just set.
Stir in the chilled cooked brown rice, frozen peas, and cooked chicken, pressing the rice down to get it slightly crispy.
Drizzle with tamari and toss everything together until well combined and heated through.
Garnish with sliced green onions before serving warm.