Step 1

Spray 6-quart slow cooker with cooking spray. In slow cooker, mix 2 cups of the onions, the chiles, garlic, seasoning mix (from taco kit) and salt. Stir in water.

Step 2

In 12-inch skillet, heat oil over medium-high heat. Cook beef roast in oil 8 to 10 minutes, turning once, until browned on both sides. Transfer to mixture in slow cooker; turn to coat. Cook on Low heat setting 7 to 8 hours, until beef is tender.

Step 3

Transfer beef to cutting board; cool slightly. Shred beef, discarding any pieces of fat. Toss beef with 1/4 cup of the cooking liquid. Place remaining cooking liquid in small bowl, for dipping.

Step 4

Fill tortillas (from taco kit) with beef, cheese, remaining 1/4 cup onions and the cilantro. Serve with salsa verde (from taco kit), reserved cooking liquid and lime wedges.