Saute onion in butter until soft. Add garlic and saute for 1 minute. In a separate pan, brown beef and pork, drain fat, and combine with onion and garlic.  Add beer, enchilada sauce, diced green chiles, cumin, and salt. Simmer for 30 minutes. Drain tomatoes well, add and simmer for additional 15 minutes. Set aside. Cut tortillas into 4 strips each. In a greased 13×9 casserole, layer ½ tortillas. Spread ½ meat mixture on top of tortilla strips. Layer all whole green chiles on top of the meat. Spread ½ cheese on top of green chiles. Layer remaining tortilla strips, remaining meat, then remaining cheese.