A fairly quick recipe that is filling and flavorful!
Peel the butternut squash with a potato peeler. Cut into thin (1/4 inch) slices, then into 1/4 inch rows and make 1/4 inch cubes (about the size of corn kernels).
Put the squash into a large skillet, and add 1/2 cup water. Cover. Let it cook, lifting the cover to stir occasionally, for about 8 minutes, or until almost tender. Add the spices, corn, black beans, tomato, cilantro, green onions and lime juice. Let it cook until the squash is just barely tender.
Meanwhile, mash the avocados and make the guacamole. Prepare any other toppings you like.
Warm a stack of corn tortillas in a wet towel in the microwave for 60 seconds. Let everyone assemble their tacos. The filling keeps well as leftovers.