Preheat the oven to 400 degrees F. Brush a non-stick or parchment-lined baking tray with the oil and set aside. Place the buttermilk in bowl. Add the chicken and toss to coat. Combine the breadcrumbs, salt, pepper, sugar, chili powder and cumin on a wide, sided plate. Coat the chicken in this mixture, gently pressing it on. Place the chicken on the baking tray. Bake 10 minutes, then turn over and bake 5 minutes more. Serve the chicken with the honey mustard sauce alongside for dipping.