What would Nobunaga think about the Bushido Code? He wouldn't know what it is. Neither would any of his contemporaries. See this thread

But that's not really what you want to know. Well this is (my English translation of the Japanese translation of) Luis Frois' description of Nobunaga

He is of average height, slender, little mustache, and has a high voice. He likes war and is constantly focused on training for war. He is very proud and very strict in delivering justice. If someone dishonours him he will without a doubt get revenge, but sometimes he displays a human and merciful side. He sleeps little and gets up early. He is not greedy, is decisive and very experienced at warfare. He [can be] incredibly impetuous and frantic but is not always so. He barely listens to the advice of his vassals, and all greatly respect him. He doesn't drink, eats little, is incredibly frank to others, and is arrogant about his own opinion. He looks down on all the other princes of Japan, and speaks to them as if they're subordinates. Everyone obeys him like an absolute monarch. Even when the fortunes of war are against him, he's calm and great at enduring hardship. He has great reason and judgement, and treats any kind of rites to God, the Buddha, pagan divination or superstition with disdain. In name at first he acts as if he belongs to Hokke Sect (Nichren Buddhism), but after attaining greatness he looks down on all idols. In a few points he follows Zen Buddhism and does not believe in the immortality of the soul or rewards and punishments in the afterlife. His house is incredibly clean, and he is incredibly meticulous in everything. He hates protracting in conversations and long preludes, and talks friendly even with lowly servants. He likes famous tea bowls, horses, swords, falconry, and really likes sumo wrestling. No one is allowed to wear weapons before him. He has a slight depressed look. Even when he meets difficulty he is fearless. Everyone obeys his every word.

So he was a good general (though what you know about his tactics/strategy is probably wrong), and was both a pragmatist and valued honour greatly. How can he do that, because his (and his contemporaries') version of honour did not clash with pragmatism. To samurai at the time, honour was about name 名, and you make a name for yourself from winning, from gaining ranks, land, and follower. He had to remove the figurehead shugo of Owari, who was his nominal superior, on his way to unite the province. But if that temporarily made him some enemies, so be it. Doing such things were extremely common in the period. In fact Nobunaga is probably one of the most loyal major daimyos of the period, if only for the fact he's head honcho from 1570 onwards and it was up to everyone else to decide if they were for or against him.