In a large skillet, brown the ground beef and drain any remaining fat. Transfer to a bowl.
Add taco seasoning, tomatoes and green chiles to the ground beef and stir to combine.
Preheat oven to 375ºF (190ºC).
Cut flour tortillas into a square shape and cut each into 4 smaller equally sized square pieces.
Generously coat a standard size muffin tin with nonstick cooking spray.
Line each cup of prepared muffin tin with a tortilla sheet.
Add 1.5 tablespoons taco mixture. Top with 1 tablespoon of cheese. Press down and add another layer of tortilla sheet, taco mixture, and a final layer of cheese.
Lightly brush the top edges of the tortilla with cooking oil.
Bake 18-20 minutes until cups are heated through and edges are golden brown.