Cook ground chuck and onion in a small saucepan over medium heat until browned, stirring until meat crumbles. Drain and pat dry with paper towels. Wipe drippings from saucepan with a paper towel. Return beef mixture to saucepan. Stir in water and next 5 ingredients. Cover and cook over low heat 5 minutes, stirring frequently.
Combine baking mix, 1/4 teaspoon chili powder, and milk in a small bowl, stirring well. Divide dough into four equal portions. Roll each portion between 2 sheets of heavy-duty plastic wrap into a 2 1/2-inch circle. Place in freezer 5 minutes or until plastic wrap can be removed easily. Invert and fit dough into 4 miniature (1 3/4-inch) muffin pan cups coated with cooking spray; remove remaining plastic wrap.
Spoon beef mixture evenly into dough-lined muffin pan cups. Bake at 400° for 8 minutes. Sprinkle each pie with 1/2 teaspoon cheese. Bake an additional 2 minutes or until cheese melts. Remove from muffin pan cups, and serve immediately.