1) The Nikkei just reports Nintendo will stop producing Wii U within 2016. It doesn't say they will necessarily start selling NX in 2016.
2) Acc. to the paper, some Wii U accessories are already not being produced anymore. Nintendo plans to deplete inventory this year
http://www.neogaf.com/forum/showpost.php?p=198908332&postcount=1
http://www.nikkei.com/article/DGXLZO98745680T20C16A3TI5000/?dg=1