Uncover pot and simmer stew until sauce thickens, about 5 minutes. Mix in cilantro and lime juice. Season with salt and pepper. (Can be made 2 days ahead. Refrigerate until cold, then cover and keep refrigerated. Rewarm before continuing.)
Heat tortillas 1 at a time on stove burner, about 10 seconds per side, turning with tongs. Cover with towel to keep warm.
Serve stew with tortillas, allowing diners to assemble tacos.