Pat the chicken breast dry with paper towels and toss in a small bowl with arrowroot powder, sea salt, and black pepper until evenly coated.
Heat the toasted sesame oil in a large non-stick skillet or wok over medium-high heat until shimmering.
Add the chicken to the skillet in a single layer and sear for 3-4 minutes per side until golden brown and cooked through, then remove and set aside.
In the same skillet, crack the egg and scramble quickly until just set, then remove and set aside with the chicken.
Add the minced garlic, grated ginger, and frozen peas to the pan, sautéing for 2 minutes until the aromatics are fragrant and peas are tender.
Stir in the cooked brown rice and coconut aminos, pressing the rice down into the pan for 2-3 minutes to allow it to crisp slightly.
Fold the cooked chicken and scrambled egg back into the rice mixture, tossing to combine, and garnish with fresh sliced green onions before serving.