Preheat oven to 400°F. Coat a 13 x 9-inch pan with cooking spray. Heat a large skillet over medium-high. Add beef and onion. Cook, crumbling beef with a spatula. Add taco seasoning, cumin and chili powder; cook until beef is cooked through. Add black beans and ¼ cup of water to skillet. Stir and heat through, about 1 minute. Pour about ⅓ cup of salsa in the bottom of baking pan (just enough to cover). Spread a thin layer of sour cream on 4 tortillas. Add to pan as next layer (it’s OK if tortillas overlap). Top with a light sprinkling of meat mixture and ⅓ of cheese. Repeat with salsa, tortillas spread with sour cream, meat and cheese until pan is full, 3 layers, ending with cheese. Bake 25 minutes, or until golden brown. Top with green onions. Kitchen Counter Per serving: 504 cal, 16g fat, 55mg chol, 30g prot, 61g carbs, 6g sugar, 11g fiber, 992mg sodium