Heat the olive oil in a Dutch oven or large wide pot over medium-high heat. Add the turkey, 1 teaspoon salt and a few grinds of pepper and cook, breaking up any clumps with a wooden spoon, until brown, about 8 minutes. Remove the turkey and set aside. Add the garlic, celery, onion and 1/4 teaspoon salt to the pot and cook, stirring occasionally, until the vegetables have softened, about 8 minutes. Add the chile powder and tomato paste and cook, stirring, 1 minute.
Return the turkey to the pot and add the diced tomatoes, beans, green chiles and chicken broth. Increase the heat to medium-high and bring to a simmer, then reduce the heat and simmer until the vegetables are tender and the flavors have melded, about 30 minutes.
Serve the chili topped with the cheese, sour cream and scallions.
Recipe courtesy of Valerie Bertinelli