A new fund with more than 100 local philanthropic investors wants to help solve some of Chicago’s biggest problems. But first, it must determine what those might be. GreenLight Fund, a Boston-based nonprofit that partners with communities to solve local issues in areas such as food security, literacy and poverty, announced Chicago as the site of its 12th fund this week. The fund will commit $6 million in Chicago over the next five years. GreenLight said its methods have been successful in solving…