What's the power steering fluid for INFINITI M35 type?

The INFINITIM35 takes recommended OEM Nissan power steering fluid. With that said, it's not a particularly picky machine -- many mass market power steering fluids, including Prestone, will do just fine. This is a bit more cost effective over using Nissan's "proprietary" blend, and it might also save You a drive to a dealership or approved retailer. Alternatively, many drivers report success with using DEX/MERC MERCON LV automatic transmission fluid in the power steering system. This is approved as a suitable substitute, and it'll likely cost You less for a large container (often sold by the gallon) versus buying an equivalent amount of dedicated power steering fluid. No matter what You choose, go with a reputable brand; but other than that, You're pretty free to make Your own determination.