Heat a large, heavy pot over medium-high. Once it’s hot, heat the olive oil, then add the chicken. Sear on each side until golden, about 3 minutes per side.
Add the tomatoes, onions, artichoke hearts and red pepper flakes and give everything a big stir. Reduce the heat to medium-low. Simmer for 20 – 30 minutes, or until the onions are transparent and the chicken is cooked through.
Shred the chicken with two forks, or skip this step. Serve and top each portion with a few capers.