I made a variation of this taco pie last night.
We had leftover (tough) steak to use up, so DH chopped it up and we heated it with the taco seasoning, can of tomato sauce, and a can of refried beans (which he was craving) for the filling. It was good. I think you could do this with leftover chicken or pulled pork, also.
When I make it again, I think I'll spoon the re-fried beans over the crust and chips as a layer, and then add some more grated cheese, instead of mixing it up with the meat. The mixture didn't look very appealing, although that didn't stop us from eating it.
I served this with Pace Piquante Sauce on the side; I forgot about the lettuce, sour cream and sliced avocado that I had planned on serving with with it.