Add chicken to a bowl. Whisk 3 tbsp olive oil, garlic, 1 tbsp lemon juice, 1 tsp salt and 1 tsp oregano together. Pour over the chicken and marinate overnight, or at least 2-3 hours.
Microwave potatoes according to package directions. Whisk remaining olive oil, lemon juice, salt and oregano in a bowl. Add cooked potatoes and toss to coat.
Thread chicken and cooked potatoes alternately on pre-soaked bamboo skewers.
Grill over medium heat until chicken is cooked on each side. Garnish with fresh parsley and lemon juice. Serve with your favourite tzatziki sauce and enjoy!