2 pounds lean ground beef
1 large onion, chopped
1/4 cup chili powder
1 jalapeo chili, chopped
12 5- to 6-inch-diameter corn tortillas
1 15-ounce can chili beans
1 1/2 cups (packed) grated sharp cheddar cheese
2 14 1/2-ounce cans Mexican-style stewed tomatoes
Preheat oven to 350F. Butter 13x9x2-inch glass baking dish. Saut beef and onion in heavy large Dutch oven over high heat until brown, about 10 minutes. Reduce heat to low. Mix in chili powder and jalapeo and saut 5 minutes. Season mixture with salt and pepper.
Overlap 6 tortillas on bottom of prepared dish, covering completely. Spoon beef mixture, then beans evenly over tortillas. Cover with remaining 6 tortillas. Sprinkle cheese over. Pour tomatoes with their juices over cheese. Bake until casserole is heated through and bubbling at edges, about 1 hour.