Season the roast on all sides with salt and pepper and place it in the bottom of your slow cooker.
Whisk together beef broth, salsa, cumin, chili powder, oregano, onion powder, and garlic powder. Pour over roast.
Cover and cook on LOW for 8 hours or until beef is tender and shreds easily. Remove roast to a large plate and shred.
Pour the sauce from the slow cooker into a saucepan over medium heat. Slowly whisk in cornstarch slurry. Cook for a few minutes until sauce begins to thicken. Taste and add additional salt and pepper, or other seasonings, if needed.
Preheat oven to 350 degrees F.
Pour ½ cup of sauce over the beef and toss. Fill each tortilla with a spoonful of shredded beef and shredded cheese. Roll up and place in the pan, seam-side down.
Pour desired amount of sauce over the enchiladas. Top with remaining cheese. Bake for 30 minutes, until bubbly.
Serve topped with optional garnishes of pico de gallo, sour cream, avocado, chopped cilantro or green onions and a side of Authentic Mexican Rice.
