Update: A correction was made to the second paragraph to clarify the combined number of nearly 200 attorneys and staff in the firm's Chicago office.Nixon Peabody LLP has named David R. Brown as the new managing partner for its Chicago office.Brown, a partner whose practice includes securities, mergers and acquisitions, private equity and business counseling, began his new role of overseeing the office of close to a combined 200 attorneys and staff last week.He succeeds Thomas M. Fahey, who led the Chicago office …