In a large mixing bowl, combine the boneless, skinless chicken thighs with gochujang, soy sauce, sesame oil, sugar, and minced garlic. Mix thoroughly until the chicken is well-coated in the marinade. Allow to marinate for at least 10 minutes.

Preheat a large skillet over medium heat for about 2-3 minutes. Add the marinated chicken, distributing it evenly across the pan. Cook for approximately 10 minutes, stirring occasionally until golden brown.

Add the chopped cabbage, sliced zucchini, and diced sweet potato to the skillet. Stir everything together and stir-fry for about 20 minutes, or until the vegetables are tender yet still maintain a pleasant crunch.

Adjust the seasoning as desired, adding more gochujang or a sprinkle of salt. Cook for an additional minute or two to meld the flavors.

Remove from heat and serve hot, alongside freshly steamed rice or in crisp lettuce wraps.