To restate the question, does Nick portray women in a negative way in The Great Gatsby? The answer is a definite yes.
Since the 1970s, some critics have raised serious questions about Nick's sexuality and whether he is struggling with accepting a same-sex preference or has, in fact, accepted his, at that time, "deviantly" labelled sexuality and has to cover it up. What lends credence to this is the scene with Mr. McKee after the party at Myrtle's apartment when they are in the elevator together and Nick later wakes up in bed in a hotel room with Mr. McKee not far away. In a novel this spare, this scene can't simply be a random accident.
Also lending credibility to this idea is not only Nick's dislike or condemnation of the major women in the novel, which would have nothing to do with sexual preference, but his visceral distaste for the female aspects of women's bodies. He has a vague dislike of Myrtle, Myrtle's sister, Jordan (very confused as he also wonders if he is in love with her), his nameless girlfriend back home, and Daisy, but beyond that a revulsion at the female body. He dislikes Myrtle's breasts and full-figured form (which are what attracts Tom). Who can forget either the visceral recoil Nick records about the line of sweat the emerges above his girlfriend's upper lip after a game of tennis? In contrast, he likes, as he repeatedly states, Jordan's hard, lean, masculine body, straight and flat chested. In general, her androgynous look appeals to him.
Beyond that, and this relates to the general sexism of the time period, not sexuality, he portrays women as liars, certainly a long-lasted sexist stereotype. Daisy, he is sure, is playing him on his first visit to her house after he moves to Long Island. Jordan he calls a liar just before he talks about how he has been leading on his girlfriend back home and not making a clean break with her. He seems to be the liar, but he calls himself cardinally honest. He portrays Myrtle as pushy, brassy, and vulgar, as well as a bully. While some of his characterizations may be true, he seems to have little sympathy for any of these woman or much sense of how life might look to them.