Copycat Wendy's Chili

In a large pot over medium heat, heat oil. Add onion, pepper, and celery and cook until softened, 5 minutes. Add in tomato paste, stirring constantly until darker in color, about 2 minutes more. Add ground beef and cook, breaking up meat with a wooden spoon, until no longer pink, about 6 minutes more. Drain fat and return to heat. Add chili powder, cumin, and garlic powder, and season generously with salt and pepper. Pour in crushed tomatoes, then fill can halfway with water, swirling to catch any remaining tomato, and add to pot. Add beans and their liquid and stir to combine. Bring chili to a boil then reduce heat to low and let simmer until flavors meld and liquid is slightly reduced, about 40 minutes. Taste and adjust seasonings as necessary. Serve chili topped with cheddar and green onions.