In a large skillet over medium-high heat, heat your oil. Add the onions and bell peppers and cook until beginning to soften, about 4 minutes. Add ground turkey and cook, stirring occasionally, until turkey is golden (it doesn't have to be completely cooked through at this point). Season with salt and pepper, then stir in garlic and tomato paste and cook until fragrant, for about 2 minutes. Transfer mixture to a slow cooker.
To the slow cooker, add in the tomatoes, beans, chicken broth, chili powder, cumin and oregano. Cook on high for 4 hours, until chili has thickened. Stir and taste and season with salt and pepper if needed.
To serve: Garnish with a little cheese and finely diced green onions. Serve with tortilla chips! Enjoy!