Preheat oven to 350°F.
Melt 1/4 cup butter and brush on taco boats.
Bake for 6-8 minutes.
Heat 1 tablespoon butter and oil in a medium pot.
Add onion and cook 5 minutes.
Stir in ground beef and cook until brown.
Add chilies and sauce and bring to a simmer.
Turn off heat and stir in 1 cup of cheese until melted.
Fill each boat with the mixture and sprinkle with more cheese.
Bake an additional 5 minutes, until cheese is melted.
Garnish with sour cream and cilantro.
Serve with chips for dipping.