Slice chicken breasts into thin pieces and place in a bowl. Add Worcestershire, onion powder, garlic powder, and pepper. Stir to thoroughly coat chicken.

Add 1 teaspoon avocado oil In a large skillet. Over medium heat cook chicken pieces until lightly browned. Turn pieces over and cook for an additional 2 to 3 minutes. Remove from skillet.

Add remaining avocado oil to warm skillet. Add onions, bell pepper and garlic and cook until slightly tender.

Turn heat off and add chicken back to skillet. Stir with veggies until fully incorporated. Place sliced cheese over mixture and cover 2 to 3 minutes to melt, then serve.