Heat oven to 450 degrees F. Line a baking sheet with aluminum foil. (If you have one that fits, lay a cooling rack inside the baking sheet, this helps get the chicken extra crispy - see note below).
In a medium bowl, whisk together the ketchup, brown sugar, vinegar, sriracha, cumin and soy sauce. Taste and adjust the sauce to your liking then set aside 1/2 cup of sauce for tossing raw chicken and save the rest for dipping once the chicken has cooked.
Toss chicken with reserved 1/2 cup of sauce then add to the prepared baking sheet (you may need two). Then, bake chicken, turning chicken once during cooking, until opaque throughout, about 30 minutes.
Serve chicken with the sauce you set aside earlier, either on the side or tossed with the chicken.