The reason why Nike makes crappy boots is because their core product of runners and sports wear is the food equivalent of Mcdonalds. To branch off into something they know even less about then making their core product is a recipe for failure. To me this would be like Mcdonalds deciding to make wine. Again, i haven't ever used them, but like the analogy of Mcdonalds and making their own wine I wouldn't need to try it to know it would be vinological feces.
Kind of like their coffee?
The real reason Nike doesn't have to make good boots is because they don't have to. Just make something soft and squishy right out of the box and they'll work great for all the snowboard posers who only ride them 2-3 times a year. Nike does a good job attracting brand whores, especially when you throw $400 pricetags on them, then offer an even shittier boot at $200 which is the one everyone actually buys, because it too has a swoosh.