Cynthia Nixon will topline a Broadway production of “Wit” this winter as part of the Rialto lineup from Gotham nonprofit Manhattan Theater Club.Nixon last appeared on the Main Stem in MTC’s “Rabbit Hole,” which netted the thesp a Tony in 2006. MTC a.d. Lynne Meadow helms “Wit,” Margaret Edson’s play about a poetry professor undergoing cancer treatments. The play opened Off Broadway in 1998 and ran for a year and a half, winning the Pulitzer in 1999 and spawning a 2001 HBO telepic that starred Emma Thompson. “Wit” is the fourth and final show to be added to the 2011-12 Broadway season at MTC’s Samuel J. Friedman Theater. The current revival of “Master Class” will be followed in the fall by “Venus in Furs,” another play landing at the Friedman following an earlier Off Broadway run. Opening in the spring is the new play by David Auburn (“Proof”), “The Columnist.” First preview is April 3 ahead of an April 25 opening. MTC’s Off Broadway slate includes two world preems, Zoe Kazan’s “We Live Here” and Molly Smith Metzler’s “Close Up Space.” At the Friedman, Meadow’s last stint at the helm was the 2010 revival of “Collected Stories.” “Wit” begins previews Jan. 5 prior to an opening set for Jan. 26. Further casting details remain to be announced.