i have been trying to get water in the nether and now i know how to do it on 1.12 versions.(1)go to the nether.(2)Then get command block with this command /give @p command_block (3)get cordinates of the place you want water (press f3 and look at the block that would be replaced by water find on f3 screen looking at and say it on chat)(4) go to chat and press up arrow on keyboard then do ctrl+c.(5)open command block and type in:setblock (ctrl+v) water (6)put button on the command block (shift click on the command block) and activate it.If you want flowing water then couse update next to the water source.