1. Heat 1 tablespoon of the oil over medium-high heat in a Dutch oven or similar large, sturdy pot. Season the chicken with salt and pepper on both sides. Once the oil is hot, add the chicken thighs in a single layer. Brown for 3 to 4 minutes on each side until light golden brown, transfer to a plate. If the chicken wont all fit in a single layer, brown it in batches. The thighs do not need to be cooked all the way through.
2. Reduce the heat to medium. To the Dutch oven, add 1 additional tablespoon oil. Add the onion and cook until beginning to soften and turn golden, about 4 minutes.
3. Stir in the green bell pepper, red bell pepper, smoked paprika, oregano, rosemary, bay leaf, and garlic. Stir constantly for 30 seconds, just until the garlic is fragrant.
4. Add the sweet potato (or Yukon gold potato), crushed tomatoes, and chicken broth. Increase the heat and bring to a rapid simmer. Turn the heat down to low and simmer gently for 15 minutes, stirring periodically.
5. Add the olives (optional), raisins (optional), and reserved chicken thighs, along with any liquid that has accumulated on the plate. Partially cover the pot and let simmer 20 additional minutes, or until the chicken is cooked through and the vegetables are tender. Remove the chicken to a cutting board.
6. Remove and discard the bay leaf.
7. Once the chicken is cool enough to handle, dice or shred, then return to the pot.
8. Stir in the sherry vinegar. Continue to simmer, uncovered, for another 5 minutes.
9. Taste and adjust seasoning (I found my stew tastes a little sweet, so I like to add a pinch of salt). Sprinkle with parsley. Serve with rice or other grains or bread.