In a large bowl, mix together ground beef, corn and black beans. Stir in taco seasoning until thoroughly combined.
In a medium bowl, mix sour cream and tomato paste together until evenly blended.
Spread half of the sour cream mixture across the bottom of a 9x13 casserole dish.
Layer 3 of the tortillas over the sour cream (you can tear one in half to make it fit better).
Add half of the meat mixture over the tortillas.
Sprinkle one cup of the cheese over the meat mixture.
Layer the remaining 3 tortillas on top of the cheese.
Spread the remaining sour cream mixture over the tortillas.
Add the rest of the ground beef over the sour cream.
Top the whole thing with the remaining cheese.
Bake for 20-25 minutes.
Recipe Notes
One slice of this calculates to be 10 Weight Watchers Freestyle Points with the ingredients I used. If you want to reduce the points you can try reducing the cheese and the sour cream by ½ cup each and using the leanest ground beef you can find.