Wall Street's AI mania is minting new battlegrounds, and few look more intriguing than Nebius Group NV (NASDAQ:NBIS) versus Palantir Technologies Inc (NASDAQ:PLTR). Both stocks are commanding nosebleed valuations, each promising to dominate a different layer of the AI stack.Track NBIS stock here.The question for investors: does the real value sit in the physical backbone of AI, or in the applications that ride on top of it?Infrastructure Vs. ApplicationsNebius, spun out of Russian roots and now making its p ...