Pat the chicken breast dry with a paper towel and season evenly with sea salt and black pepper.
Heat the avocado oil in a large cast-iron skillet or wok over medium-high heat until shimmering.
Add the chicken to the skillet and sear until golden brown and cooked through, approximately 6 to 8 minutes.
Remove the chicken from the pan and set aside on a plate.
In the same skillet, add the broccoli, red bell pepper, and snap peas, stir-frying for 3 to 4 minutes until tender-crisp.
Stir in the minced garlic and grated fresh ginger, cooking for 30 seconds until fragrant.
Return the chicken to the skillet and pour in the tamari and toasted sesame oil, tossing everything together to coat.
Garnish with sesame seeds and serve immediately.