Preheat the oven to 425°F. In a medium bowl, rub the chicken with 1 tablespoon harissa and 1 tablespoon olive oil. Season salt and pepper, then set aside.
On a large sheet pan, toss the butternut squash and chickpeas with the remaining olive oil and harissa. Season with salt and pepper and spread in an even layer. Roast for 20 to 25 minutes, until the squash edges begin to brown, and the chickpeas are crispy in parts.
Add the marinated chicken to the sheet pan in an even layer. Return to the oven for 6 to 9 minutes, until chicken is cooked through. Sprinkle with feta and cilantro just before serving.