Naruto would die because the Kyuubi would bust out. If you're asking what would happen next then the answer is fairly straightforward, they'll have to capture it again and find a new host. Presumably someone with excellent chakra control, regenerative abilities and willpower.
That would mean Kurama is free. Naruto's body would be consumed (most likely burn up completely like what happens when he goes 4+ tails) and only Kurama would stand I'm guessing.