In a medium saucepan saute onion in butter until translucent.
Season with garlic salt and remove from heat.
Shred/debone your rotisserie chicken
Add shredded chicken to the onion mixture along with 2 cups cheddar cheese
Gently fill corn tortilla shells with 1-2 scoops of chicken & cheese mixture
Place seam side down on a lightly greased cookie sheet.
Drizzle with enchilada sauce, top with additional cheese and Chugwater Chili Seasoning
Bake at 400° for 20-30 minutes until golden brown.