Line a baking sheet with parchment paper. Preheat oven to 350°F.
Place sweet potatoes on prepared sheet and roast at 350°F for 45 minutes to 1 hour or until a knife can easily pierce the potatoes.
While potatoes are roasting, caramelize onion in a large sauté pan lightly coated with evoo over medium-high heat, about 7 to 10 minutes, until dark and very soft.
Add red pepper, garlic, and chicken and continue cooking until chicken is light golden brown, about 8 to 10 minutes.
Add cumin, coriander, cinnamon, broth, and chickpeas. Reduce heat to a simmer.
Cut potatoes in half lengthwise and scoop out potato flesh, leaving about a quarter-inch of flesh to support filling without breaking.
Add scooped potato to chicken mixture and stir to combine. Adjust seasoning with salt and pepper.
Add spinach and stir into hot chicken mixture. Divide filling between potato halves. Sprinkle olives on top and drizzle with tahini.
Before serving, reheat potatoes until filling is bubbly. Garnish with more tahini and sliced scallions.
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