Rub pork w/ taco seasoning or mix taco seasoning w/ broth. Put pork in crockpot, pour broth over meat. Cook until meat shreds easily (takes mine about 6 hours on low).
Reserve cooking liquid. Shred pork & set aside.
Put enough oil in frying pan to cover bottom. Chop onion & sautee on medium heat. Shred zuchini & add to pan. Add cooking liquid, 1/4 C at a time, to keep moist. When vegetables are soft & liquid is mostly absorbed, add shredded pork (& enough cooking liquid so that pork doesn't dry out), soup, & 3 C cheese.
Spray 9 x 12 pan with cooking spray. Add enough red enchilada sauce to cover bottom of pan. Place 1/2 C or so pork mixture into tortilla, roll, & place in pan, seam side down. Continue until you're out of tortillas. Pour remaining sauce over tortillas to cover them. Sprinkle remaining cheese on top. Spray foil, & cover pan.
Bake at 350 for 30 minutes. Remove foil & back 2 more minutes. Let sit 5 minutes.