Toss chicken breast in the oil, kosher salt, chili powder, onion powder, cayenne pepper, oregano, paprika, and sugar. Place in grill and close lid grill for 4-5 minutes or until chicken is cooked through.
Remove and let cool slightly and chop into ½ inch strips. Lay the tortillas on a clean work surface and divide the shredded cheddar over half of the tortillas. Then spread the chicken evenly on top of the cheese with the chopped scallions. Sprinkle with kosher salt and top with a tortilla (like a sandwich). Then one by one place on the grill. Close the lid and grill for about 3 minutes or until crisp.