For the marinade, combine all ingredients in a small bowl and stir to combine. Set aside.
Thread chicken onto skewers, alternating with capsicum and onion. Repeat until you run out of ingredients.
Add skewers to a large container with a secure lid and pour over marinade, tossing to coat evenly. Place in the frdge to marinate for 2 hours, tossing every hour.
Grill skewers for 3-4 minutes on each side or unitl chicken is cooked through.
Notes
If you can't find fresh herbs then simply substitute with a 1/3 tsp dried parsley and 2/3 tsp dried thyme.
If you're really in a rush to get dinner on, you can reduce the marinading time. Just keep in mind that the longer you can marinade them, the better they with taste!