Put a large heavy-bottomed skillet over medium-high heat and add the oil. Working in batches, add the beef to the skillet, season with salt and pepper, and cook until it is well browned, 10 to 15 minutes.
To the slow cooker sleeve, add the onions, jalapenos, 1 tablespoon chile powder, cinnamon, red pepper flakes, garlic, and strained tomatoes (reserve the juice). Add the seared beef to the slow cooker. Pour the reserved tomato juice into the skillet, scrape up any browned bits, and pour into the slow cooker. Cover the slow cooker and cook on low for 4 to 6 hours.
In a small bowl, combine the sour cream, remaining 1 teaspoon chile powder, lime juice, and hot sauce and mix until well blended. Keep covered in the refrigerator until the chili is done and ready to serve.
Taste and adjust the seasoning. (Reserve 2 cups for the Round 2 Recipe Beef and Bean Burritos). Serve garnished with the sour cream mixture.