Heat a large Dutch oven over high heat. Coat pan with cooking spray. Add 1 1/4 pounds beef to pan; cook 4 minutes or until browned, stirring to crumble. Place cooked beef in a bowl. Repeat procedure with cooking spray and remaining 1 1/4 pounds beef. Add onion, poblano pepper, and garlic to pan; cook 5 minutes, stirring occasionally. Return beef to pan. Stir in chili powder, chipotle chile powder, and cumin; cook 1 minute. Add tomato paste and beer, scraping pan to loosen browned bits; cook 2 minutes. Add 3 1/2 cups beef stock to pan; bring to a boil. Combine remaining 1/2 cup beef stock and flour in a bowl, stirring with a whisk. Add flour mixture to pan, stirring constantly with a whisk. Stir in oregano, salt, and tomatoes; bring to a boil. Reduce heat, cover, and simmer 45 minutes, stirring occasionally. Remove pan from heat. Reserve 7 cups chili for Chili Potpie with Cheddar Biscuits and Chili Stroganoff. Divide remaining 6 cups chili among 4 bowls; top evenly with diced avocado, sliced fresh chiles, if desired, and cilantro sprigs.