Preheat the oven broiler.
In a large, non stick saute pan over medium high heat, melt the butter.
Add the chopped onion and cook for a few minutes, until starting to soften.
Add the ground round and cook, breaking up the meat into small pieces, until no longer pink.
Stir in the chili beans, tomatoes, salt, chili powder, smoked paprika and Worcestershire sauce.
Bring the chili to a boil. Turn down the heat and allow to simmer, uncovered, for 5 - 10 minutes.
Transfer the chili to a deep dish pie plate. Top the chili with the shredded cheese.
Place the pie under the broiler to melt the cheese.
Top the pie with the Fritos. Serve the Walking Taco Casserole with lettuce, tomato, sour cream and taco sauce.