Pat the beef chuck cubes dry with paper towels. In a large bowl, toss the beef with 1 tablespoon of flour, salt, and pepper.

Heat olive oil in a large skillet over medium-high heat. Sear the beef on all sides until deep brown and caramelized, working in batches if necessary. Remove with a slotted spoon and set aside.

In the same skillet, reduce heat to medium. Add diced onion and bell pepper, scraping up browned bits. Sauté for 5-7 minutes until softened.

Add garlic, chili powder, cumin, oregano, and paprika. Cook for 1 minute, stirring constantly until fragrant.

Sprinkle remaining 1 tablespoon flour over the mixture and cook for another minute.

Transfer everything from the skillet to the slow cooker, including the seared beef. Add diced tomatoes (with juice), beef broth, and green chiles. Stir well to combine.

Cover and cook on LOW for 8 hours or HIGH for 4 hours, until beef is fork-tender.

Taste and adjust seasoning with salt and pepper. If gravy is too thin, remove beef and reduce briefly in a pot, or thicken with a cornstarch slurry (1 tbsp cornstarch with 2 tbsp water, stirred in and cooked 2-3 minutes). Garnish with chopped cilantro before serving.