Usually I poach mine the night before in half chicken stock/half water with cumin, tabasco, red pepper flakes, chili powder, salt, black pepper, a little oregano and if I have them a couple of chipotles and the adobo sauce they're packed in. Then I shred them the night i want them and reheat them in a reduction of the reserved liquid.
edited to add: definitely with shredded cheddar or jack!!