Add chicken to large freezer bag
Whisk together buttermilk, onion powder, garlic powder, salt and pepper and pour over chicken
Add herbs and seal bag
Marinate at least 2 hours but preferably overnight
Add contents of bag to slow cooker (or Instant Pot)
Cover and cook on high in slow cooker for 3-4 hours or low for 6-8 (or set pressure cooker to manual for 15 minute and do a natural pressure release)
Optional: Line a baking sheet with foil and place chicken on baking sheet under broiler for 3-4 minute or until skin is browned and crispy
Serve garnished with additional fresh herbs or as desired