Richard Dreyfuss did not receive an Oscar nomination for portraying Roy Neary in Close Encounters of the Third Kind.
Roy Neary is rather odd to be our "hero" for the film because many of his character traits are more often looked at problematic. Even before he meets the UFO we see Roy with his family where he is probably a little too short with both his wife and children. I suppose it was very important to have Dreyfuss in the lead, oppose to someone like Jack Nicholson, because in Roy's semi outbursts in this early scene Dreyfuss does not have an overt intensity about himself. Dreyfuss simply has that average guy quality in his performances so even when he lashes out against the various annoyances that his family provides for him Dreyfuss does not make Roy seem like a psychopath but rather just a rather exasperated father. Of course technically speaking Roy only becomes worse though when he is called away to check on a downed power line only to accidentally come into contact with an alien spacecraft.
After coming in contact with the alien Roy becomes obsessed with it which seems to go even further than even a normal obsession from a more normal human intrigue. His mind clearly has been directly changed by the influence of the ship as he never stops thinking of a single physical structure. This is a unhealthy obsession actually as it causes him to lose both his job as well as his family. Dreyfuss's performance is important here because he never makes Roy's seem irresponsible man or a cold man even though Roy is basically closing himself off from his present day reality in this obsession. Dreyfuss is good in portraying this as just kinda an overwhelming pull in Roy that is forcing him to constantly think about structure. Dreyfuss does not even show it to be a problem so to speak, but rather something that has become in Roy's nature. Although the obsession is still self-destructive Dreyfuss does a fine job of making it seem less severe than it is.
Roy after finding out the physical location that matches the shape in his mind he sets off to reach it despite apparently being evacuated do to an apparent leak of poisonous gas. Dreyfuss's role becomes relatively simple at this point as Roy just continues to try to reach his destination despite there being many obstacles in his path. Dreyfuss though continues to be good in the role as he quietly reflects how each thing affects Roy's demeanor. On one hand he's good in portraying the determination but as well as the frustrations at each obstacle that even includes the U.S. army. Dreyfuss though is probably best in portraying the eventual wonderment as Roy seems closer to his objective showing it to be a truly profound discovery whenever he sees something relating to the aliens. He helps create the grandeur of the final scenes as he basically realizes the event as Roy finally fulfilling this uncontrollable need that motivated since he saw the UFO. Richard Dreyfuss does not given an overly complex performance here. Frankly by not making Roy anything but a normal guy going through these things he manages to make his character's actions less troubling. Dreyfuss gives a good performance by avoiding bringing too much pathos to Roy, and just helping to create the wonderment the aliens are meant to evoke in this film.