  We devise an approach to describe the electronic instabilities of doped
multi-walled nanotubes, where each shell has in general a manifold of Fermi
points. Our analysis relies on the scale dependence of the different scattering
processes, showing that a pairing instability arises for a large enough number
of Fermi points as a consequence of their particular geometric arrangement. The
instability is enhanced by the tunneling of Cooper pairs between nearest
shells, giving rise to a transition from the Luttinger liquid to a
superconducting state in a wide region of the phase diagram.
