Heat oil in a large saucepan over medium-high heat. Add onion and garlic; sauté 2 minutes, stirring frequently. Add pork; cook 5 minutes, browning on all sides. Stir in chili powder, cumin, salt, and red pepper; cook 30 seconds, stirring constantly. Stir in broth and tomatoes; bring to a simmer. Cover, reduce heat, and simmer 1 1/2 hours or until pork is almost tender, stirring occasionally. Stir in butternut squash; simmer 30 minutes or until pork and squash are tender.