Heat the olive oil in a large skillet over medium-high heat. Add the diced onion and green bell pepper and cook for 3 to 4 minutes, stirring occasionally, until they soften and start to pick up a little color.

Add the minced garlic and cook for 30 seconds until fragrant. Add the ground turkey to the skillet, breaking it up with a wooden spoon into small crumbles. Cook for 6 to 8 minutes, stirring regularly, until the turkey is fully cooked through with no pink remaining and has developed some light browning. This browning adds a lot of flavor to the finished chili.

Stir the tomato paste and all the dry spices, including chili powder, cumin, smoked paprika, salt, pepper, and cayenne if using, directly into the skillet with the turkey. Cook and stir for 1 minute so the spices bloom in the heat. This step makes the chili taste rounded instead of raw.

Transfer the turkey mixture to the slow cooker. Add the drained black beans, fire-roasted tomatoes with their juices, green chiles, and chicken broth. Stir everything together so the ingredients are evenly distributed.

Cover and cook on LOW for 6 to 8 hours or on HIGH for 3 to 4 hours. The chili will thicken as it cooks. If it gets too thick near the end, stir in a splash more broth.

About 10 minutes before serving, stir in the lime juice. Taste and adjust salt or chili powder as needed. Serve hot in deep bowls topped with shredded cheddar cheese, a dollop of sour cream, diced avocado, or sliced green onions.