Chris Cuomo is demanding that his bosses at NewsNation move his new show to a different time slot — his latest, desperate bid to improve his sagging viewership on the fledging cable-TV network, The Post has learned. Cuomo — who joined NewsNation Oct. 3 after getting fired from CNN for secretly helping his older brother, ex-Gov. Andrew Cuomo, navigate a slew of sex scandals — is fuming about the lackluster performance of his nightly broadcast, which currently airs at 8 p.m., Monday to Friday, sources said.