Slice the chicken breasts into thin, even pieces so they cook quickly and evenly. Once sliced, pat the chicken dry with paper towels to remove excess moisture, which helps it brown properly instead of steaming in the pan.

In a small bowl, whisk together the soy sauce or coconut aminos, vinegar, minced garlic, grated ginger, and low-carb sweetener. Whisk until the mixture looks smooth and well combined, then set it aside so the flavors can blend while you cook the chicken.

Heat the oil in a large skillet over medium-high heat until hot but not smoking. Add the chicken in a single layer, working in batches if needed to avoid overcrowding. Let it cook undisturbed for a couple of minutes until lightly golden, then stir and continue cooking just until the chicken is fully cooked through. Transfer the chicken to a plate and set aside.

Using the same skillet, add the vegetables and cook over medium-high heat, stirring frequently. Cook until they are crisp-tender and vibrant in color, making sure they retain a bit of bite rather than becoming soft or mushy.

Return the cooked chicken to the pan with the vegetables and pour the prepared sauce evenly over everything. Gently toss to combine, making sure the chicken and vegetables are well coated.

Continue cooking for a short time, stirring gently, until the sauce thickens slightly and clings to the chicken and vegetables without becoming too thick or sticky.

Remove the skillet from the heat and serve immediately while hot, or divide into portions for meal prep once slightly cooled.