The PC beta for Fallout 76 has been launched and things are not looking good for PC gamers. According to reports, the game does not feature any FOV slider and there isnt any way that you can increase or decrease it via its config files. And since Bethesda has announced that the game will not support mods, we may not see a FOV slider anytime soon.
Source: N4G PC Fallout 76 does not feature FOV slider or support 16:10/21:9 monitors, game speed tied to framerate