Not going to happen. If an "alliance" such as that was going to happen, it would be far more likely to be between Nintendo and Sega.
Sony is primarily an electronics company, and Nintendo is primarily a videogames company. Sony Computer Entertainment is just one division of Sony, while gaming is Nintendo's entire business. At the same time, the Japanese game industry is not failing. Last I checked, Japanese companies weren't the ones losing hundreds of millions if not billions of dollars. Additionally, I don't imagine their business philosophies would match. Sony (for whatever reason) prides themselves on high cost products with low margins. They're also more focused on hardware than software.
Basically, even if they have mutual interests, their policies don't match up very well at all.
