Heat olive oil in a Dutch oven over medium-high heat. Season beef with salt and pepper and sear on all sides until browned. Add garlic, cumin, and chili powder. Pour in salsa verde and bring to a simmer. Cover and cook on low for 1½–2 hours until beef is tender. Shred beef with forks and mix back into sauce. Warm tortillas and fill with shredded beef. Top with cilantro, diced onion, queso fresco, and lime juice.
Notes
Use slow cooker or Instant Pot for alternative cooking methods. The beef can be made ahead and reheated for taco night.