Pat the chicken breast dry with paper towels and cut into 1-inch bite-sized pieces.
Season the chicken pieces evenly with the 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 in a single layer and sear until golden brown and cooked through, about 5 to 6 minutes.
Remove the cooked chicken from the pan and set aside on a clean plate.
In the same pan, add the broccoli florets and 2 tablespoons of water, then immediately cover with a lid to steam for 2 to 3 minutes until tender-crisp.
Remove the lid and add the minced garlic, grated ginger, and red pepper flakes, sautéing for 1 minute until fragrant.
Return the chicken to the pan and pour in the tamari and toasted sesame oil.
Toss all ingredients together for 1 more minute to allow the sauce to glaze the chicken and broccoli before serving.