To make the taco seasoning—in a small bowl combine chili powder, cumin, black pepper, oregano, paprika, and crushed red pepper flakes.
Trim any visible fat off of the pork roast. Place the roast into the bottom of the slow cooker. Sprinkle garlic on top of the roast. Sprinkle the taco seasoning evenly on top of the roast. Pour in the vegetable broth around the roast. Cover and cook on high for the first 3 hours. Then cook on low for 5 hours.
Remove the pork and shred it using two forks. Return the pork to the slow cooker and mix with the juice.