Warm the oil in a large skillet over medium heat. Add the onion and bell pepper.
Cook, stirring, until softened, about 4–5 minutes.
Add the garlic and cook 30 seconds until fragrant.
Crumble in the ground turkey. Season with salt and pepper. Cook, breaking it up with a spatula, until browned and no longer pink, 5–7 minutes.
Stir in chili powder, cumin, smoked paprika, oregano, and red pepper flakes.
Toast the spices for 30–60 seconds to bloom the flavors.
Add tomato paste and stir to coat the meat. Mix in the drained diced tomatoes and broth. Bring to a gentle simmer.
Reduce heat to medium-low and cook 4–6 minutes, stirring occasionally, until the mixture thickens and the flavors come together.
Adjust salt to taste.
Turn off the heat. Stir in lime juice. Sprinkle the cheese evenly over the top, then cover for 1–2 minutes to melt.
Top with cilantro if using.
Serve hot with your favorite low-carb sides or in lettuce cups.