Preheat the oven to 350. Brown ground beef, drain and add taco seasoning according to the instructions. Lay unbaked crescent rolls on the bottom of a 9x13 pan. Put taco 1/2 of the taco meat on top of the crescent rolls. Put all of the sour cream on top of the meat mixture. Crush Doritos and put 1/2 of the Doritos on top. Layer the rest of the taco meat on top, and cover with the remaining Doritos. Sprinkle the cheese over the top and bake for 20 minutes.