To make Carnitas: Spray 5-quart slow cooker with cooking spray; trim roast of excess fat, and place in slow cooker. Sprinkle with taco seasoning mix, reserving 1 tablespoon for nachos. Pour chicken broth over roast. Cover; cook on High heat setting 4 to 5 hours, or Low heat setting 8 to 9 hours, or until tender. Remove from slow cooker, and shred with fork. Reserve 2 cups shredded pork for nachos. Save remaining for another use.