Heat a large skillet or wok over medium-high heat and coat with a light spray of avocado oil.
Add the diced chicken breast, sea salt, and black pepper, sautéing for 5-6 minutes until golden and cooked through.
Move the chicken to the outer edges of the pan and add the toasted sesame oil to the center.
Stir in the minced garlic, grated ginger, and the frozen peas and carrots, cooking for 3 minutes until fragrant and tender.
Incorporate the chilled cooked brown rice, using a spatula to break up any large grains and mixing it thoroughly with the chicken and vegetables.
Create a well in the center of the mixture, crack the egg into it, and scramble until just set before folding it into the rest of the dish.
Pour the tamari over the rice and stir-fry for an additional 2 minutes to allow the flavors to meld and the rice to develop a slight crisp.
Remove from heat, garnish with the freshly sliced green onions, and serve warm.