Set your oven to 425°F to preheat.
In a large sheet pan, combine chicken thighs, sweet potatoes, and red onion with olive oil, honey, kosher salt, oregano, rosemary, chili powder, smoked paprika, granulated garlic, cumin, coriander, allspice, and minced garlic. Toss everything well so the ingredients are thoroughly coated, then arrange them evenly in a single layer on the pan.
Place the sheet pan in the oven and roast for 30 to 35 minutes until the chicken is fully cooked (internal temperature of 165°F) and the sweet potatoes have softened and started to caramelize.
While roasting, prepare the yogurt sauce by adding lemon zest, lemon juice, and garlic to a mini food processor. Pulse until the garlic is finely chopped.
Add the Greek yogurt, olive oil, dried dill, and salt to the processor and blend until smooth and combined.
Once the chicken and vegetables are done, serve them hot alongside the fresh yogurt sauce for dipping or drizzling.