Toss cabbage with 1 tbsp wine vinegar in a bowl and set aside to lightly pickle.

Heat 1 tbsp olive oil in a large frying pan over medium heat. Cook chicken for 6-8 minutes, until golden and cooked through. Remove from the pan and set aside.

Add 1 tbsp olive oil to the same pan. Cook red bell pepper and onion, covered, for 2 minutes until slightly softened. Uncover and sauté until lightly golden.

Stir in fajita seasoning. Return chicken to the pan and cook for a few minutes until heated through, adding a splash of water if needed. Season to taste.

Warm tortillas per package instructions.

Serve tortillas with chicken mixture and pickled cabbage.