Cynthia Nixon is back on Broadway in Marjorie Prime, a new play now in previews at the Helen Hayes Theater. The Tony Award winner recently visited Live with Kelly and Mark to discuss her latest project, also praising her co-star June Squibb, who plays the title role at 96 years old. "She is unreal....She is there, scene after scene, getting her laughs and getting her moving moments. You can't even believe it." Nixon …