Combine tomatoes, green bell pepper, red bell pepper, Cubanelle pepper, onion, garlic, and cilantro in the bowl of a food processor; pulse until finely chopped. Set aside 1 cup of sofrito for the recipe and save the rest for another use.

Heat olive oil in a large skillet over medium heat. Season chicken thighs with adobo and cumin. Add chicken to hot skillet and sear on each side until golden brown, 5 to 6 minutes per side. Reduce heat to low and add chicken broth and 1 cup of sofrito. Cover and simmer until chicken thighs fall apart, about 1 hour.