Just guess:
A10 7870k is $137, which I will suppose production is $70, which double that would be $140, which is the as much as xbox one but on a higher clock, so xbox one chip should be no more than $100, where the nx chip, assuming it has 20 gcn cores to exceed ps4, can be produced at $120. And if nintendo go with 4 zen instead of 8 excavator, the production should be at $100. Since nintendo are going to grab lots of them, the actual price should be around $120.
The ram should be no more than $80 even for 8 GB of HBM2.
The board and primarry storage(32 gb) should be $60.
The psu should be no more than $20.
There you have $400 for the primary nx console bundle with storage and a controller.
For the handheld, k12 should be around $15 per core, or in nintendo's case where clock is lowered, the pirce should be $20 total. Two extra low frequency a53 should be $10. The gpu should be about $30, and $20 for other soc functions, where the total would be $80, and since it is soc the price should be lower and nintendo can get for actual $80. The board and main storage would cost another $20. The battery should be $15, and 16GB sd card for $15. The control should be $20, and screen for $50. There you have $250 for the handheld with more capability than an iPhone 5s and a handheld exclusive game.