Pat chicken thighs with paper towel to remove all moisture.
Season well with salt and pepper.
Add olive oil to a Dutch oven over medium high heat. Sear chicken thighs on all sides making sure to get a nice golden brown colour (you might need to do this in batches if your Dutch oven is not large enough).
Remove the chicken thighs to a baking sheet and set aside.
To Dutch oven add onions and garlic and sauté for a few minutes. Once onions are translucent add tomatoes and stock, and return the chicken to the Dutch oven. Bring to a boil, cover and reduce heat to medium low. Cook for 20-25 minutes. Uncover, and sprinkle with dried thyme.