Start browning ground beef. When it’s about halfway cooked, add the onion and jalapeño and salt and pepper to taste. Drain and set aside.
For the sauce:
Melt the butter in a large skillet or saucepan. Add the flour and stir till combined and just starting to brown. Add garlic powder through chicken broth and cook over medium to medium low heat until sauce is warm and thickened.
To assemble the enchiladas:
Grease a 10x13 casserole dish. Take each tortilla and lightly dip in the sauce. Then fill with meat and top with a spoonful of cheese. Roll and place seam side down in the pan. When pan is full, top with remaining sauce and cheese. .