Preheat the oven to 425˚F with a rack positioned in the bottom third.

In a small bowl, mix the paprika, cumin, garlic powder, salt, and pepper to combine. Halve and core the pears. If working with Bosc or Concorde pears, cut them into 6 wedges; cut Forelles into quarters; and halve seckels.

On a 13-by-18-inch rimmed baking sheet, combine the pear wedges, potatoes, and carrots. Drizzle with 1 tablespoon of the olive oil, sprinkle with about one-third of the spice mixture, and toss to coat everything evenly. Spread the pears and vegetables out in an even layer. Rub the chicken thighs with the remaining 1 tablespoons of oil. Sprinkle both sides with the remaining spice mixture to coat well. Place the chicken thighs over the pears and vegetables, spacing them out evenly.

Place the sheet pan in the bottom third of the oven and roast until the internal temperature of the chicken registers between 170 to 175˚F on an instant-read thermometer, 40 to 45 minutes.

Transfer the chicken thighs to a platter and tent with foil to keep warm. Switch the oven to broil, and place the sheet pan on a rack positioned about 6-inch below the heating element. Broil the pears and vegetables until lightly browned in spots and the juices on the pan begin to caramelize, about 5 minutes. Turn them as needed to brown evenly and prevent scorching.

Divide the pears and vegetables among plates, along with some of the accumulated juices on the pan. Top with the chicken. Sprinkle with the cilantro and a dollop of sour cream, and serve.