Place first 4 ingredients (ground beef through garlic) in a Dutch oven over medium-high heat; cook and stir until beef crumbles and is no longer pink; drain well.
Stir in next 6 ingredients (tomatoes through chili powder). Bring mixture to a boil then reduce heat, cover and simmer for 15 minutes, stirring occasionally.
Stir in corn; cook, uncovered, for 15 minutes or until squash is tender and chili has thickened.