Preheat to 425°F. Line two rimmed baking sheets with parchment paper or foil.

Toss the potatoes with olive oil, garlic powder, paprika, salt, and pepper. Spread them cut-side down on one baking sheet.

Pat the drumlets dry. Toss with vegetable oil, salt, and pepper, then arrange in a single layer on the second baking sheet.

Place both pans in the oven. Roast the potatoes for 35–45 minutes, turning once, until browned and tender. Roast the chicken for 30–40 minutes, turning halfway through, until browned and its internal temperature reaches at least 165°F.

In a small saucepan, combine the peanut butter, coconut milk, soy sauce, lime juice, honey, ginger, garlic, sesame oil, and optional chili. Cook over medium-low heat for 3–5 minutes, stirring until smooth. Add warm water a tablespoon at a time if the sauce is too thick.

Set aside about one-third of the sauce for serving. During the final 5 minutes of roasting, brush the chicken generously with the remaining sauce. Return it to the oven until glazed and lightly caramelized.

Spoon the reserved satay sauce over or alongside the chicken. Serve with roasted potatoes and garnish with cilantro, green onions, peanuts, and lime wedges if desired.