Heat oil in a large pot over medium high heat and season the beef with salt, black pepper, cumin, garlic powder, and oregano.
Brown the beef in batches until deeply seared, then remove and set aside.
Sauté the diced onion in the same pot until softened, add garlic, and cook briefly until fragrant.
Stir in the potatoes and roasted green chiles and cook for about 1 minute.
Return the beef to the pot and add beef broth and water, scraping up browned bits.
Bring to a boil, then reduce heat to low, cover, and simmer 1½ to 2 hours until beef is tender.
If desired, stir in a flour and water slurry during the last 10 minutes to thicken the broth.
Adjust seasoning, turn off heat, and let rest briefly before serving.